SILAFAE 2026

30 Nov 2026, 08:00 → 4 Dec 2026, 18:00 America/Bogota

Universidad de los Andes

Alexis López (UNAL) (Universidad Nacional de Colombia) , Andres Flórez (Uniandes) (Universidad de los Andes) , Carlos Sandoval (UNAL) (Universidad Nacional de Colombia) , Carlos Ávila (Uniandes) (Universidad de los Andes) , Deywis Moreno (UAN) (Universidad Antonio Nariño) , Diego Restrepo (U. de Antioquia) (Universidad de Antioquia) , Eduardo Rojas (U. de Nariño) (Universidad de Nariño) , Gabriela Navarro (UAN) (Universidad Antonio Nariño) , Mario Acero (U. de Atlantico) (Universidad del Atlantico) , Oscar Zapata (U. de Antioquia) (Universidad de Antioquia) , Richard Benavides (ITM) (Universidad de Nariño)

The XVI Latin American Symposium on High Energy Physics, SILAFAE 2026, will take place at Universidad de los Andes, in Bogotá, Colombia, from November 30th until December 4th, 2026. The symposium will bring together the Latin American community working on high-energy physics and other fellow scientists from around the world to discuss modern topics in particle physics. This event aims to foster  collaboration, discuss new ideas and strengthen ties for the advancement of fundamental science.  

Abstract submission opening day: May 19th / 2026
Deadline to submit abstracts: October 23rd / 2026

Deadline for registration: November 6th / 2026

The early registration fee, until October 23rd 2026,  is:

• Faculty: 200 USD
• Students and Postdocs: 120 USD

Registration fee after October 23rd 2026:

• Faculty: 250 USD
• Students and Postdocs: 150 USD

The fee covers lunches, coffee breaks and other activities. If you make the registration fee payment with credit card, please select the option "Colombian Pesos". 

Financial support may be available for a limited number of students. Only students who submit an abstract for a talk or a poster are eligible for this financial aid. Unfortunately, funding for international airfare is not available. 

Confirmed Plenary Speakers:

• Prof. Kajita Takaaki (Nobel Prize Laureate), University of Tokyo, JP, Neutrino Oscillations.
• Prof. Chang Kee Jung, Stony Brook University, USA, Experimental Neutrino Physics. 
• Prof. Yossi Nir, Weizmann Institute of Science, ISR, Theoretical perspectives on flavor physics.
• Prof. Arely Cortes, University of Tokyo, JP,  Higgs boson searches in the ATLAS experiment.
• Dr. Chris Polly, Fermilab, USA, Results and perspectives from g-2 experiment.
• Prof. Cristina Mantilla Suárez, University of Virginia, USA, Results from The Light Dark Matter eXperiment (LDMX). 
• Prof. Camilo García-Cely, IFIC Valencia, SP, Self Interacting Dark Matter Theory.
• Prof. José Ramón Espinosa, IFT Madrid, SP, Vacuum Decay in the SM. 
• Dr. Dilia María Portillo, TRIUMF Lab., CA, Outreach in experimental HEP.
• Prof. Hernán Wahlberg, Universidad de la Plata, AR, BSM Searches in the ATLAS Experiment. 
• Prof. Diego Aristizabal, Universidad Técnica Federico Santa María, CL, Dark Matter and Neutrinos Theory.
• Prof. Myriam Mondragon, UNAM, MX, BSM Physics Theory.
• Prof. Alexis Aguilar-Arévalo, UNAM, MX, Experimental results from CEvNS.
• Prof. Diego Milanes, UTEC, PE, Results from the LHCb Experiment. 
• Prof. Marcela Peláez, Universidad de la República, UY, Low energy QCD and massive gluons.
• Prof. Carlos Ávila. Universidad de Los Andes. COL, PPD and Interdisciplinary  Applications.

 

About Bogotá:

Nice video about Bogotá from the experience of different international visitors

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                Colombian Network of High Energy Physics

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Monday, 30 November

08:00 → 09:00 Registration

09:00 → 09:30 Opening

09:30 → 10:15 Plenary Talk: Neutrino Oscillations

Convener: Prof. Takaaki Kajita (University of Tokio)

10:15 → 11:00 Plenary Talk: Experimental Neutrino Physics

Convener: Prof. Chang-Kee Jung (Stony Brook University )

11:00 → 11:30 Coffee Break

11:30 → 12:15 Plenary Talk: CEvNS Precision Measurements and Dark-Sector Particle Signals

Convener: Prof. Diego Aristizabal (Universidad Técnica Federico Santa María)

12:15 → 13:00 Plenary Talk: Experimental results from CEvNS

Convener: Prof. Alexis Aguilar-Arevalo (UNAM)

13:00 → 14:30 Lunch Break

14:30 → 17:00 Parallel Talks: Parallel Talks SD-704

14:30 BSM searches on neutrino oscillations at NOvA

As an accelerator-based long-baseline neutrino experiment studying neutrino oscillations, NOvA has been searching for signals of beyond the Standard Model (BSM) physics like sterile neutrinos and non-standard interactions (NSI) with matter, setting constraints on the parameters governing those new-physics phenomena. In addition, we are also investigating NOvA's capabilities to observe the effects of a possible invisible neutrino decay on the neutrino oscillation data. In this talk I will present the current status of NOvA on these BSM searches, focusing on the most resent results on sterile neutrinos, the progress on improving the constraints on the NSI parameters, and the sensitivity studies of neutrino decay signals.

Speaker: Mario Andres Acero Ortega (Universidad del Atlantico)

14:55 Statistical Constraints on E₆ Gauge Extensions via Sanson–Flamsteed CEνNS Analysis from CONUS+ data

The first reactor-antineutrino observation of coherent elastic neutrino--nucleus scattering (CE$\nu$NS) by the CONUS+ experiment provides a unique opportunity to test well-motivated gauge extensions of the Standard Model. Using the CONUS+ recoil spectrum, we investigate light vector mediators arising in $E_6$-inspired scenarios, including benchmark models such as $Z_\chi$, $Z_\psi$, and $Z_{B-L}$, within the unified Sanson--Flamsteed parametrization. Exclusion regions at 90% confidence level are obtained for the mediator mass and coupling strength.

Speaker: Christian Martínez Benavides (Universidad de Nariño)

15:20 Disentangling Lorentz Invariance Violation and Non-Standard Interactions in Long-Baseline Neutrino Experiments

Long-baseline neutrino experiments offer excellent opportunities to probe physics beyond the Standard Model. Non-standard interactions (NSI) and Lorentz-invariance violation (LIV) can both modify neutrino oscillation probabilities and, in certain regions of parameter space, produce similar phenomenological signatures. Such degeneracies may make it difficult to identify the underlying origin of an observed deviation from the standard three-flavor framework.

In this work, we investigate the possibility of distinguishing NSI and LIV effects at future long-baseline neutrino experiments. We study the degeneracies between these two new-physics scenarios and assess the sensitivity of representative experimental configurations to their discrimination. Our analysis highlights the potential of future neutrino oscillation measurements to not only discover deviations from the standard paradigm, but also shed light on the nature of the underlying new physics.

Speaker: Mehedi Masud (PUCP, Lima, Peru)

15:45 JUNO constraints on Lorentz-violating coefficients and implications for neutrino mass ordering

Using the 59.1-day publicly released JUNO spectrum, we investigate isotropic Lorentz-invariance violation (LIV) in reactor antineutrino oscillations within the minimal Standard Model Extension framework. We perform two-dimensional $\Delta\chi^2$ scans for selected CPT-even and CPT-odd LIV coefficient combinations, considering both normal and inverted mass ordering. From these scans, we derive correlated and individual constraints on the isotropic LIV coefficients and study their effects on the $\sin^2\theta_{12}$$-$$\Delta m^2_{21}$ parameter space. We find that LIV can modify the allowed regions, with the size of the shifts depending on the coefficient combination and mass-ordering hypothesis considered. These results illustrate how the released JUNO spectrum can probe isotropic Lorentz-violating effects and their interplay with neutrino mass-ordering studies.

Speaker: Tatiana Araya-Santander (Universidad Católica del Norte)

16:10 Statistical Analysis of Non‑Standard Neutrino Interactions and Leptophilic Gauge Extensions in CONUS+

The first observation of coherent elastic neutrino--nucleus scattering (CE$\nu$NS) with reactor antineutrinos by the CONUS+ collaboration has established a new precision probe of neutrino interactions at low energies. Using the recently released CONUS+ dataset, we study the sensitivity of reactor CE$\nu$NS measurements to non-standard neutrino interactions (NSI) and to the leptophilic gauge extension $U(1)_{L_e-L_\mu}$, deriving exclusion regions at 90% confidence level from the measured recoil spectrum.

The CONUS+ observation is fully consistent with Standard Model expectations, reinforcing the predictive power of CE$\nu$NS while constraining new neutrino interactions. Our results provide competitive and complementary limits to those obtained by other CE$\nu$NS and low-energy neutrino experiments, highlighting the potential of reactor-based measurements as precision tools for neutrino physics and searches for physics beyond the Standard Model.

Speaker: Mr Cristian Santiago Muñoz López (Universidad Mariana)

16:35 Exact and Hybrid Probabilities of Neutrino Oscillations in a Uniform Medium

We examine the oscillations between three neutrino flavors propagating in matter of constant density, using the evolution operator combined with the Lagrange interpolation formula and Vieta’s identities of the Hamiltonian. This gives us exact, closed-form expressions for Pee, Pμe, and Pμτ that are compact and structurally identical to their vacuum counterparts. Each probability is a sum of terms weighted by coefficients that depend on matter only through the eigenvalues ​​and elements of the Hamiltonian matrix. CP violation appears as a single term proportional to the Jarlskog invariant J. No mixing angles or CP phase are required in matter, clearly separating genuine CP violation from matter-induced effects. We explicitly verify that when the potential vanishes, our formulas reduce to those for the vacuum. Since exact eigenvalues ​​involve non-illuminating trigonometric expressions, We complement our study with a hybrid approach, in which, in the expressions of the exact probabilities, the exact eigenvalues ​​are replaced by the approximate ones expressed in terms of radicals, which are obtained by two successive rotations of the Hamiltonian. The resulting probabilities are exactly unity for any choice of eigenvalues. For a DUNE-like setup, they reproduce the exact results with absolute errors less than 2 × 10⁻⁶ in all channels, for both neutrinos and antineutrinos.

Speaker: Dr José Arnulfo Herrera

14:30 → 17:00 Parallel Talks: Parallel Talks SD-716

14:30 Linking the Baryon Asymmetry of the Universe to Neutrino Masses through Leptogenesis

The observed baryon asymmetry of the Universe remains one of the central open questions in particle physics and cosmology. Leptogenesis provides a compelling explanation by relating the generation of the matter–antimatter asymmetry to new sources of lepton-number and (CP) violation beyond the Standard Model.

In this work, we investigate leptogenesis within effective descriptions and high-energy extensions of the Standard Model, in which the structures responsible for neutrino masses may also generate a lepton asymmetry in the early Universe. We discuss the main ingredients required for successful leptogenesis, including the out-of-equilibrium dynamics of heavy states, the generation of (CP) asymmetries, washout effects, and the subsequent conversion of the lepton asymmetry into a baryon asymmetry through electroweak sphaleron processes.

Speaker: Ricardo Zamora (Universidad Católica del Norte)

14:55 Dark matter and lepton sector phenomenology of a radiative inverse seesaw model

We propose a Standard Model (SM) extension where neutrinos get masses through a two-loop inverse seesaw mechanism. This naturally explains the smallness of the neutrino masses and allows seesaw mediators to be at the TeV scale with testable phenomenology. The model adds two real singlet scalars and four electrically neutral leptons to the SM. The extension considers the existence of two global Abelian symmetries, a continuous $U(1)$ and a discrete $Z_{3}$. The latter, remains unbroken after spontaneous symmetry breaking and forbids tree-level and one-loop neutrino masses, and stabilizes the dark matter (DM) candidates. This setup accommodates neutrino-oscillation data, yields two pseudo-Dirac heavy pairs with small active–sterile mixing, and predicts an effective Majorana mass $m_{ee}$ in the $2.1-4.4$ meV range for normal ordering. Charged-lepton flavor violation is naturally suppressed yet testable: for a representative benchmark we obtain $BR(\mu \rightarrow e \gamma)\simeq 1.6 \times 10^{-14}$, with correlated signals in $\mu \rightarrow eee$ and $\mu-e$ conversion within next-generation experimental reach. Altogether, the radiative origin of neutrino masses links low-energy flavor observables to collider signatures, delineating discovery targets for MEG~II, Mu2e/COMET, and the HL-LHC and distinguishing this framework from conventional inverse- and radiative-seesaw models.

Speaker: Rocío Branada Balbontín (Universidad Técnica Federico Santa María)

15:20 Which Neutrino Texture Zeros Are Viable in the Hermitian Dirac Sector?

Reducing the number of free parameters while retaining the ability to explain the observed phenomenology of the lepton sector remains an important task in flavor physics. In particular, viable theoretical frameworks must reproduce the measured neutrino mass squared differences and mixing angles, while providing predictions or constraints on the still not fully determined CP violating phase. In this context, texture-zero approaches provide a useful framework for identifying predictive patterns in the neutrino mass matrices by imposing vanishing entries and thereby reducing the number of independent parameters.

In this work, we investigate different texture zero patterns and analyze their compatibility with current neutrino oscillation data for both normal and inverted mass orderings. We first consider the case of Dirac neutrinos and identify texture structures capable of reproducing the observed lepton sector phenomenology. We then extend the analysis to the Type-I seesaw mechanism, imposing texture zeros in the Dirac neutrino mass matrix while working in a basis where the right handed Majorana mass matrix is diagonal. The phenomenological viability of the resulting textures is systematically examined against the current neutrino oscillation observables. Our results provide a framework for identifying the most predictive texture structures and for reducing the parameter space associated with neutrino mass generation.

Speaker: Richard Benavides (ITM)

15:45 Neutrino masses and dark matter stability

Despite the Standard Model’s great success in describing fundamental particles and their interactions, it fundamentally lacks a dark matter particle candidate to account for the Universe’s observed relic abundance. Furthermore, the mechanism responsible for generating neutrino masses remains one of the Standard Model’s enduring mysteries. In many compelling extensions, both dark matter stability and non-zero neutrino masses arise naturally from the spontaneous symmetry breaking of global symmetries. In this talk, we will review various theoretical scenarios that propose a common new physics origin for both dark matter stability and neutrino mass generation, and we will discuss the phenomenology of such models.

Speaker: Cesar Bonilla (Universidad Católica del Norte)

16:10 Non-Vanilla Sterile Neutrinos: Long-Baseline Signatures and BSM Connections

Long-standing experimental anomalies have driven an extensive search for eV-scale light sterile neutrinos, though conclusive evidence remains elusive. Notably, recent results from Fermilab experiments have ruled-out the traditional sterile neutrino explanation for these anomalies. However, long-baseline accelerator experiments offer a unique probe for very light sterile signatures. In this talk, we present a modified light sterile neutrino framework capable of producing distinct signatures at long baselines. We further demonstrate how this scenario naturally bridges sterile neutrino physics with broader Beyond the Standard Model (BSM) sectors.

Speaker: David Vanegas Forero (Universidad de Medellín)

16:35 Active–Sterile Neutrino Oscillations: Matter Effects in Scotogenic Models with Gauged \(U(1)_{B-L}\) Symmetry

The observation by KM3NeT of a neutrino with an energy exceeding (100\,\mathrm{PeV}) motivates the study of scenarios that could account for this event alongside the absence of comparable events in IceCube. One possibility is that sterile-to-active neutrino conversion depends on propagation conditions within the Earth. For the geometry considered, the estimated propagation distances are approximately (147\,\mathrm{km}) through rock and water before reaching KM3NeT and (14\,\mathrm{km}) through ice before reaching IceCube. This difference motivates the hypothesis of an astrophysical sterile neutrino flux whose conversion into active states is modified by matter effects. In this work, we study two extensions of the Standard Model with gauged (U(1)_{B-L}) symmetry, in which a new (Z') boson mediates interactions between neutrinos and terrestrial matter, while a scotogenic sector generates radiative contributions to neutrino masses and active–sterile mixing. We analyze how these interactions modify conversion probabilities and assess their implications for both detectors. We also explore the phenomenology of the dark matter candidates present in these models.

Speaker: Juan Felipe Jiménez Román (Instituto de Física, UNAM)

14:30 → 17:00 Parallel Talks: Parallel Talks SD-802

14:30 A new measurement of the $K^{+} \rightarrow \pi^{+}\nu\bar{\nu}$ branching ratio at the NA62 experiment

The $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay is a golden mode for flavour physics. Using data collected in 2016--2022, NA62 announced the first observation of this decay with a signal significance above $5\sigma$ and the measurement $B(K^{+}\rightarrow\pi^{+}\nu\bar{\nu}) = \left(13.0^{+ 3.3}_{- 3.0} \right)\times10^{-11} $. New results from the analysis of the 2023--2024 dataset are presented. This dataset doubles the effective sample size, leading to a $5\sigma$ expected sensitivity for the Standard Model process. Reconstruction and selection algorithms have been improved, boosting sensitivity and reducing the background contamination. An updated measurement of the branching ratio is presented and prospects for the full 2016--2026 dataset are discussed.

Speaker: Prof. Michal Zamkovsky

14:55 New results on rare and radiative kaon decays from the NA62 experiment

The NA62 experiment at CERN collected a large sample of in-flight $K^+$ decays during Run 1 (2016-2018) and resumed data taking in 2021, with operations foreseen through 2026. This talk presents new preliminary results from NA62 based on data collected up to 2024. These include the first observation of the decay $K^+\to\mu^+\nu\mu^+\mu^-$, precision studies of rare and radiative kaon decays such as $K^+ \to e^+ \nu \gamma$ and $K^+ \rightarrow \pi^+ \pi^+ \pi^- \gamma$, and improved measurements of their branching ratios. The excellent kinematic reconstruction, timing resolution, and trigger performance of the NA62 detector enable effective background suppression and high-precision measurements. Preliminary results improving the precision of the experimental state-of-the-art are presented.

Speaker: Atakan Akmete

15:20 New physics searches with kaon and pion decays at NA62

Searches for the decays $K^{+}\rightarrow\pi^{+}X$ and $\pi^{+}\rightarrow e^{+}N$ are presented using data collected by the NA62 experiment in 2016-2022 and 2017-2024, respectively. Results are interpreted to constrain a range of new physics scenarios covering all four portal model scenarios. Upper limits on the $K^{+}\rightarrow\pi^{+}X$ branching ratio are established at the $10^{-11}$ level, providing constraints on dark photon, scalar and ALP couplings. From the search for heavy neutral lepton production in $\pi^{+}\to e^+N$ decays of beam pions, upper limits of the extended neutrino mixing matrix element $|U_{e4}|^2$ are established at the $10^{-8}$ level over the heavy neutral lepton mass range 95-126 MeV/$c^2$.

Speaker: Cristina Biino (INFN (Turin))

15:45 Dark Z in the Light of the Recent NA62 Results

Rare kaon decays constitute a sensitive probe in the search for new physics, since flavour-changing neutral-current interactions are absent at tree level in the Standard Model and are highly suppressed at the loop level. Processes such as $K^+ \to\pi^++$ invisible are particularly interesting in searches for light new particles that couple weakly to the Standard Model and can be produced through flavour-changing transitions. We study the decay $K^+\to\pi^+Z_d$ with a dark $Z_d$ in the context of a $U(1)_d$ dark two-Higgs-doublet model with a complex scalar singlet. In this model, the second Higgs doublet and the scalar singlet are charged under $U(1)_d$, while Standard Model fermions are neutral. The dark gauge boson $Z_d$ acquires mass through the spontaneous breaking of the electroweak and dark gauge symmetries and couples to the Standard Model through $Z$-$Z_d$ mass mixing. The kaon decay is induced at the one-loop level by the flavour-changing transition $s\to dZ_d$. We compute the one-loop contributions from diagrams involving $W^\pm$ bosons, charged Higgs bosons, charged Goldstone bosons, and up-type quarks. We also study the consistency of the parameter space by imposing theoretical and experimental constraints on the scalar sector and confront the model with current bounds from low-energy observables and rare kaon decay measurements.

Speaker: Javier Enrique Molina Ariza (Universidad Nacional Autónoma de México)

16:10 QCD Effects in Lepton-Number-Violating Meson and Tau Decays

Lepton-number-violating (LNV) meson and tau decays provide complementary probes of new physics that violate lepton number by two units. Below the electroweak scale, short-range contributions mediated by heavy particles can be described by a dimension-9 low-energy effective Lagrangian. While operators involving first-generation fermions are strongly constrained by neutrinoless double beta decay, operators with more general flavor structures can be tested through processes such as $M_1^- \to M_2^+\ell_1^-\ell_2^-$ and $\tau^- \to \ell^+M_1^-M_2^-$.

In this talk, I will discuss two complementary QCD aspects required for a complete interpretation of these decays. First, I will present the one-loop QCD renormalization-group evolution of the dimension-9 operator basis. The general flavor structure induces mixing not only among different Lorentz structures, but also among operators with different quark-flavor configurations. This evolution leads to new constraints on previously unbounded operators and can significantly modify the limits on individual Wilson coefficients.

Second, I will address the non-perturbative hadronic matrix elements entering LNV meson decays. Standard estimates commonly rely on the vacuum-insertion approximation and neglect connected contractions between the two quark currents. We evaluate these connected contributions using the $1/N_c$ expansion and show that they can provide significant corrections to the factorized result. Since they constitute leading contributions in the large-$N_c$ expansion of the non-perturbative QCD effects, they provide a systematic first approximation toward a complete lattice-QCD determination of the relevant matrix elements. Together, these results improve the connection between experimental searches for LNV decays and constraints on the underlying effective operators.

Speaker: Marcela González (Universidad de Valparaíso)

16:35 Charged lepton flavor violating decays $Z\to \ell_\alpha\ell_\beta$ in the inverse seesaw

After confirmation of the massiveness and mixing of neutrinos, by neutrino oscillation data, the origin of neutrino mass and the occurrence of charged-lepton-flavor non-conservation in nature have become two main objectives for the physics of elementary particles. Taking inspiration from these two matters, we address the $Z$-boson lepton decays $Z\to\ell_\alpha\ell_\beta$, with $\ell_\alpha\ne\ell_\beta$, thus violating charged-lepton flavor. We calculate the set of contributing one-loop Feynman diagrams characterized by virtual neutral leptons, both light and heavy, emerged from the inverse seesaw mechanism for the generation of neutrino mass. We obtain general analytical results, which decouple in the limit as $\Lambda\to\infty$, with $\Lambda$ the high-energy scale involved in the inverse seesaw mechanism. Our quantitative analyses consider two scenarios of heavy-neutral-lepton mass: (1) the mass spectrum is degenerate; and (2) a more complete framework which includes both degenerate and non-degenerate mass spectra. The quantitative estimations we perform in both scenarios take into account upper bounds on non-unitarity deviations in the lepton mixing matrix and perturbativity of Yukawa couplings. We find that, even though current constraints on $Z\to\ell_\alpha\ell_\beta$, by the ATLAS Collaboration, remain far from inverse-seesaw contributions, improved sensitivity from in-plans machines, such as the Future Circular Collider and the Circular Electron Positron Collider, shall be able to probe this mass-generating mechanism through the decay $Z\to\tau e$, whose contributions could be as large as $10^{-7}$.

Speaker: Adrián González Quiterio (Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla)

14:30 → 17:00 Parallel Talks: Parallel Talks SD-803

14:30 Supernova neutrino flavor composition: non-adiabatic MSW evolution and shock-wave effects

Predicting the flavor composition of supernova neutrinos is a challenging task due to the high-density conditions in the stellar interior, where neutrino self-interactions can significantly modify flavor evolution. Considering a broad range of possible post-collective neutrino flavor states, we study the range of flavor compositions that can be obtained for supernova neutrinos arriving at Earth. We numerically investigate the subsequent three-flavor MSW evolution through the stellar envelope, focusing on departures from the adiabatic approximation and on the effects of idealized time-dependent shock-wave profiles. For a given non-adiabatic evolution, we quantify how assumptions on the post-collective state constrain the final flavor composition by comparing the areas of the corresponding allowed regions in ternary plots with that obtained for a fully arbitrary initial state. We study this quantity for different neutrino energies and post-bounce times, providing a quantitative characterization of how the stellar density profile affects the flavor-composition constraints of supernova neutrinos.

Speaker: Dr Gabriel Damián Zapata (ICN - UNAM)

14:55 HNL decays in the GeV mass range: Multihadron final states

Heavy neutral leptons (HNLs) in the GeV mass range can decay through a rich variety of semileptonic hadronic channels. We study HNL decays into two- and three-pseudoscalar meson final states through both charged- and neutral-current interactions. The aim is to improve the description of exclusive HNL hadronic decays in the GeV region and to assess their impact on the total HNL decay width relevant for experimental searches. Incorporating phenomenological form factors constrained by hadronic tau decays, we present preliminary results for several multihadronic channels.

Speaker: NESTOR QUINTERO POVEDA (Universidad del Tolima, Colombia)

15:20 A Flavored Peccei-Quinn Symmetry for Axions, Flavor, and Neutrino Masses

Recent measurements by several experimental collaborations have reported deviations from Standard Model (SM) predictions in diphoton final states, potentially hinting at the existence of intermediate scalar resonances above the electroweak scale. Such anomalies can be naturally accommodated within SM extensions featuring an enlarged scalar sector. In particular, multi-Higgs doublet frameworks arise in Flavored Axion Models (FAMs), which have been proposed to explain the texture zeros of quark mass matrices. These models provide a unified description of quark masses and the Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix while simultaneously addressing the strong CP problem. In this work we study a concrete FAM realization augmented with Majorana masses for right-handed neutrinos, implementing a type-I seesaw mechanism. In this model the flavor structure is effectively determined by the vacuum expectation values of the scalar doublets and Yukawa couplings of order one. Within this framework, neutrino and axion mass scales are intrinsically connected, as the heavy right-handed neutrinos obtain their masses from the scalar field responsible for the spontaneous breaking of the Peccei-Quinn symmetry. We further explore the phenomenological implications of the model, including constraints from flavor-changing neutral currents derived from semileptonic decays, as well as current experimental limits on the axion-photon coupling obtained from axion search experiments.

Speaker: Eduardo Rojas Peña (Universidad de Nariño)

15:45 Impact of Isospin-Violating Dark Matter interactions on the neutrino fog

As dark matter direct detection experiments reach sensitivities at which solar neutrinos begin to be observed, understanding and investigating the “neutrino fog” is becoming increasingly important. This background is not fixed and is strongly linked to the assumed properties of dark matter. In this work, we study the neutrino fog by considering Isospin-Violating Dark Matter (IVDM) models. We will discuss how these non-standard couplings of dark matter to protons and neutrons can cause shifts in the expected limits of these backgrounds through different detection materials. Furthermore, we will study specific dark matter models to illustrate some conditions that might be required to suppress this background. The impact of systematic errors is also discussed

Speaker: Laura Duque Herrera (Cinvestav)

16:10 Fermionic Dark Matter and Lepton Flavor Violation in a Scotogenic--Seesaw Model

We study an extension of the scoto--seesaw model in a fermionic dark matter scenario, where light neutrino masses arise from both tree-level and one-loop contributions through the type-I seesaw and scotogenic mechanisms, respectively. The solar and atmospheric neutrino mass scales then arise naturally from these two contributions. In the scotogenic model, achieving an efficient annihilation rate for fermionic dark matter generally requires sizable Yukawa couplings. However, these same couplings also induce lepton flavor violating processes, which can lead to tension with current experimental constraints. The model considered here introduces an additional annihilation channel mediated by the scalar field and controlled by a new coupling. This provides an alternative contribution to the dark matter annihilation rate without necessarily requiring large values of the Yukawa couplings associated with lepton flavor violation.

Speaker: Emmanuel León López (Universidad Nacional Autónoma de México)

16:35 Probing sub-GeV dark matter at DUNE ND-LAr

Sub-GeV dark matter coupled to a dark photon provides a well-motivated framework for exploring dark sectors. In this talk, we will focus on inelastic dark matter, discussing the mechanisms that determine its relic abundance and the prospects for probing its parameter space with DUNE’s liquid-argon cube, which is part of the near detector (ND-LAr).

Speaker: Amalia Betancur Rodríguez (Universidad EIA)

14:30 → 17:00 Parallel Talks: Parallel Talks SD-804

14:30 Detector development and commissioning of TAMBO-4 pathfinder array

TAMBO-4 is a compact array developed as an initial prototype for the Tau Air-Shower Mountain-Based Observatory (TAMBO), a future experiment designed to detect Earth-skimming astrophysical tau neutrinos through extensive air showers in the Colca Valley, Arequipa, Peru. The detection of tau neutrinos in the PeV energy range with TAMBO is essential for multimessenger astrophysics, flavor physics, and searches for physics beyond the Standard Model. The TAMBO-4 prototype consists of four plastic scintillator detector panels, each with an active area of approximately 1.5 m² formed by 16 scintillator bars coupled to a SiPM photosensor through wavelength-shifting optical fibers. The detectors are arranged in a triangular geometry and deployed at the campus of the Pontificia Universidad Católica del Perú. TAMBO-4 is optimized for the detection of atmospheric air showers initiated by primary cosmic rays in the 10–100 TeV energy range and serves as a testbed for detector instrumentation, calibration procedures, timing synchronization, and event reconstruction techniques. The detector readout and acquisition systems were developed using Red Pitaya-based and micro-DAQ solutions, together with a dedicated synchronization system aimed at achieving precise timing measurements for air-shower reconstruction. We report on the current status of the detector development and commissioning of TAMBO-4, including scintillator panel construction, DAQ implementation, noise reduction studies and detector calibration using vertical muons MIP measurements and radioactive source mapping. In parallel, detailed simulations based on CORSIKA and GEANT4 are being used to characterize detector performance, optimize the array geometry, and study the expected angular reconstruction capabilities. Preliminary performance studies and first commissioning results demonstrate the potential of TAMBO-4 as a platform for validating detector technologies and reconstruction methods for the future TAMBO deployment.

Speaker: José Luis Bazo Alba (Pontificia Universidad Católica del Perú)

14:55 The Pierre Auger Observatory as a Cosmo-Geophysics Laboratory

The Pierre Auger Observatory, located near Malargüe, Argentina, is the world's largest facility dedicated to ultra-high-energy cosmic rays. The Observatory combines about 1600 water-Cherenkov detectors over 3000 km² with 27 fluorescence telescopes. After more than two decades of operation, this hybrid design has made it a unique laboratory for phenomena beyond cosmic-ray astrophysics. The CosmoGeophysics Task Force coordinates this interdisciplinary program. In space weather, the surface detector has recorded low-threshold counting rates (scalers) since 2005. These rates reveal Forbush decreases linked to interplanetary coronal mass ejections. Sixteen years of these publicly available, very low-noise data have established them as a new proxy of solar activity. In atmospheric electricity, a dedicated fluorescence-detector trigger has recorded ELVES since 2013. These are transient luminous events in the lower ionosphere produced by strong lightning. Their microsecond resolution allows lightning geolocation to within a few kilometres. The world's largest sample of multiple ELVES ruled out the ground-reflection explanation for triple ELVES and revealed halos. Cameras installed in 2023–2024 enabled simultaneous sprite observations. The surface detector has also observed downward terrestrial gamma-ray flashes, which last tens of microseconds and cover up to 200 km². They include the first flashes with an asymmetric azimuthal structure, suggesting sources more complex than a simple downward beam. Lightning detection systems, a new electric-field mill network being deployed for the AugerPrime radio upgrade, and a planned lightning-mapping array will link lightning development to gamma-ray emission. We review the origins of the CosmoGeophysics task force, its main results, and its prospects, highlighting opportunities for the Latin American high-energy and geophysics communities.

Speaker: Luis Nunez (Universidad Industrial de Santander)

15:20 Pierre Auger Observatory. From UHECR Observatory to Multidisciplinary Scientific Hub

The Pierre Auger Observatory in Argentina was conceived as the world’s largest facility dedicated to the study of ultra-high-energy cosmic rays (UHECRs). More than two decades of operation have transformed it into a broader scientific platform where frontier astroparticle physics, detector innovation, multi-messenger astronomy, geophysics, atmospheric science, and open data initiatives increasingly converge. Its original hybrid configuration, combining a 3000 km² surface array of water-Cherenkov detectors with fluorescence telescopes, has evolved over time, first through the low-energy extensions HEAT and the Infill array, and later through the underground muon detector, the radio detector, and AugerPrime, the Observatory's major upgrade. The resulting multi-hybrid observatory provides enhanced sensitivity to UHECR mass composition, extends searches for ultra-high-energy photons and neutrinos, and strengthens Auger’s role in multi-messenger astronomy. This evolution extends beyond Auger itself. The Observatory has become a unique test environment—or scientific “playground”—where other collaborations can deploy, operate, and cross-calibrate new instrumentation using Auger infrastructure, coincident air-shower measurements, and the technical expertise of its personnel. Examples include FAST prototypes for next-generation fluorescence detection, layered water-Cherenkov detectors developed as part of the PEPS initiative, and the recently deployed ARISE radio array. The site has also supported complementary atmospheric and space-based investigations, notably cooperation with ESA's Aeolus mission, in which Auger fluorescence telescopes detected laser light emitted by the satellite’s ALADIN lidar. Meanwhile, Auger data support studies of solar modulation, space weather, atmospheric conditions, and ionospheric ELVES, while its open-data and education programs broaden access to the facility. We present this evolution as an example of how long-term high-energy physics infrastructure in Latin America can become a multidisciplinary scientific hub, connecting fundamental science, emerging detector technologies, international collaborations, and regional capacity building.

Speaker: Luis Nunez (Universidad Industrial de Santander)

15:45 Beyond Cosmic Rays: The Evolution of LAGO into a Multidisciplinary Scientific Observatory

We present the evolution of the Latin American Giant Observatory (LAGO) from an initiative that emerged from the Pierre Auger Observatory to a multidisciplinary research and innovation ecosystem. Initially conceived as a geographically distributed network of water Cherenkov detectors (WCDs) at high-altitude sites to study high-energy gamma-ray bursts, LAGO has progressively expanded its scientific scope, technological capabilities, and societal impact. Today, the collaboration integrates astroparticle physics, space weather, atmospheric radiation, and environmental monitoring within a framework of standardised instrumentation, advanced simulations, and FAIR-compliant data workflows.
Central to this evolution is transforming the WCD into a modular scientific appliance, supported by the ARTI simulation framework, which enables site-specific, time-dependent modelling of cosmic-ray fluxes and detector responses. This approach extends LAGO's capabilities beyond its original scientific objectives to applications such as space weather monitoring, particularly in regions influenced by the South Atlantic Magnetic Anomaly; volcanic muography; cosmic-ray neutron sensing for soil moisture monitoring and precision agriculture; and environmental background radiation studies.
Complementing these developments, LAGO is building a distributed digital infrastructure that integrates edge computing at detector sites with regional and international computing resources, facilitating open science, reproducibility, and collaborative data analysis. Through sustained education, capacity building, and international cooperation, LAGO has strengthened scientific communities across Latin America and Spain while fostering new applications that connect fundamental research with regional challenges and societal needs.

Speaker: Christian Sarmiento Cano

16:10 Building the Next Generation of Latin American Scientists: Research-Based Training through LA-CoNGA and EL-BONGÓ Physics

Training the next generation of researchers in high-energy and astroparticle physics requires more than advanced coursework. Students must develop expertise in theory, scientific computing, detector instrumentation, and the collaborative practices of large experiments, alongside transferable skills relevant to careers beyond academia. In Latin America, however, unequal access to fellowships, modern laboratories, research infrastructure, and stable early-career opportunities limits this training, particularly where local instrumentation facilities and international mobility are scarce.
We present two ERASMUS+ capacity-building initiatives, LA-CoNGA physics and EL-BONGÓ physics, designed to address these disparities through scalable, cross-border, research-based education. Their approach combines open online learning resources, shared software and data repositories, and remotely accessible laboratories that can be operated through low-bandwidth SSH connections. A three-month research apprenticeship, hosted by a regional laboratory or conducted remotely, connects coursework to authentic projects while developing research practices, teamwork, and technical autonomy.
Building on LA-CoNGA physics, which concluded in January 2024, EL-BONGÓ physics began in January 2025 and extends the collaboration to three Central American countries. It organises training around four research-and-learning communities: high-energy physics, multimessenger astronomy, seismology and Earth hazards, and artificial intelligence and computational tools. Two additional features reinforce its research-oriented model: courses structured around concrete scientific problems that let students learn through active research participation; and a network of fabrication laboratories (FABLabs) that provides practical training in digital fabrication, low-cost instrumentation, and local maintenance.
Together, these initiatives illustrate how shared digital infrastructure, project-based learning, and regional cooperation can broaden access to advanced scientific training, strengthen institutional capacity, and improve graduates' readiness for academic and non-academic careers.

Speaker: Prof. Gabriela Navarro (Universidad Antonio Nariño)

17:00 → 18:00 Cocktail

Tuesday, 1 December

09:00 → 09:45 Plenary Talk: Higgs boson searches in the ATLAS experiment.

Convener: Prof. Arely Cortés (University of Tokyo)

09:45 → 10:30 Plenary Talk: Higgs boson searches in the CMS experiment

Convener: Prof. Jose David Ruiz Alvarez (Universidad de Antioquia)

10:30 → 11:00 Coffee Break

11:00 → 11:45 Plenary Talk: BSM Searches in the ATLAS Experiment

Convener: Prof. Hernán Wahlberg (Universidad de La Plata)

11:45 → 12:30 Plenary Talk: BSM Searches in the CMS Experiment

Convener: Prof. Helena Brandao (Rio de Janeiro State University)

12:30 → 14:00 Lunch Break

14:00 → 16:30 Parallel Talks: Parallel Talks SD-704

14:00 Advancing the Precision Frontier in Top-Quark Physics: New Predictions for $t\bar{t}VV$ Production

As it is widely known, the top quark plays a central role in modern studies of the Standard Model (SM) and the search for physics beyond it. As the heaviest known elementary particle, its strong coupling to the Higgs boson makes it particularly relevant for probing the electroweak sector and exploring possible deviations from SM predictions. In this context, precision studies have become an essential strategy, requiring increasingly accurate theoretical predictions for SM processes that may constitute \textbf{backgrounds} to potential signals of new physics for example for $t\bar{t}t\bar{t}$ production.

Motivated by this challenge, our work focuses on SM background processes involving top-quark pair production in association with two electroweak gauge bosons, $t\bar{t}VV$, with $V=W,Z$. We present a Monte Carlo event generator incorporating next-to-leading-order (NLO) QCD corrections matched to parton showers, representing the first implementation of these processes within the POWHEG framework. This combination is essential for improving the theoretical description of relevant kinematic observables and providing realistic simulations of collider events.

These developments provide a valuable tool for phenomenological studies of complex final states, particularly for characterizing SM backgrounds relevant to four-top-quark production and searches for new physics at the LHC. Beyond their phenomenological applications, this work contributes to strengthening expertise in precision collider physics in Latin America, fostering scientific collaboration and expanding opportunities for regional participation in the LHC physics program.

Speaker: Luz Silvana Rodriguez Melendez (UNAM)

14:25 A Boosted Decision Tree for Signal and Background Discrimination in Boosted $HH\to b\bar{b}b\bar{b}$ Searches

The production of Higgs boson pairs provides a direct probe of the Higgs sector and its self-interactions. However, searches in the $HH\to b\bar{b}b\bar{b}$ final state face substantial challenges due to the large multijet background. In the boosted regime, where each Higgs boson is reconstructed as a large radius jet, combining kinematic and jet substructure information offers an opportunity to improve signal and background discrimination.

This work presents the development and evaluation of a boosted decision tree (BDT) classifier for the boosted gluon-gluon fusion ($ggF$) $HH\to b\bar{b}b\bar{b}$ analysis. The classifier combines event-level kinematic observables with jet substructure variables to exploit correlations that are not fully captured by individual discriminating variables. Its performance and stability are assessed through four-fold cross-validation, yielding area under the receiver operating characteristic curve (AUC) values between 0.73 and 0.78. The model is further examined using SHapley Additive exPlanations (SHAP), which identify physically motivated observables, particularly the pseudorapidity separation between the Higgs boson candidates and their reconstructed masses, as important contributors to the classification.

Finally, the BDT score is incorporated into a binned statistical fit and compared with the invariant mass of the Higgs boson pair, $m_{HH}$. Under statistical-only assumptions, the expected upper limit on the signal strength improves from $\mu=8.61$ to $\mu=6.99$, corresponding to an improvement of approximately 20\%. These results demonstrate the potential of multivariate classification to enhance the sensitivity of boosted di-Higgs searches by exploiting the multidimensional structure of signal and background events.

Speaker: José Alejandro Portela Robayo (Universidad Nacional de Colombia (CO))

14:50 Optimizing Ditau Mass Reconstruction with Deep Learning: Toward Experimental Applications

As key fundamental questions about nature remain unsolved, searches for physics beyond the Standard Model and precision measurements have become increasingly relevant throughout the years. In particular, tau physics has gained particular interest due to the role of third-generation fermions in many BSM scenarios, where enhanced couplings to the third generation can lead to distinctive signatures involving tau leptons. One of the main observables that can help us discriminate between signal and background in ditau channels is the reconstructed mass of the tau pair. However, this mass reconstruction is challenging, as crucial information is lost due to the neutrinos present in the decay, which are not directly detectable in the LHC context.
This talk focuses on the development, optimization, and evaluation of a deep neural network (DNN) for the mass reconstruction of the ditau system, with future experimental applications in mind. The DNN is evaluated in terms of mass resolution and its potential for signal-background discrimination, using a hypothetical (Z') particle resonance as the case study and three different benchmark models: the Sequential Standard Model, the (B-L) model, and the 4321 model.

Speaker: Angie Catalina Parra Ovelencio (Universidad de los Andes)

15:15 Tau Polarization as a Discriminator for BSM Particles in Ditau Final States

Motivated by potential excesses observed in third-generation fermion channels at the LHC, many proposed SM extensions predict new particles that couple preferentially to tau leptons, such as leptoquarks, $Z'$ bosons, and Type-II two-Higgs-doublet models. These scenarios can be distinguished through tau polarization, a crucial observable for separating scalar from vector particles in ditau final states.

This phenomenological work improves upon traditional maximum-likelihood techniques by employing machine learning algorithms. By developing a robust polarization estimator, this approach separates competing particle hypotheses, thereby enhancing the sensitivity of searches for physics beyond the Standard Model.

Speaker: Jose Antonio Reyes Vega (Universidad de los Andes (CO))

14:00 → 16:30 Parallel Talks: Parallel Talks SD-716

14:00 Spin Identification of Dark Sector Mediators through Angular Distributions

Spin correlations between the production and decay of Long-Lived Particles (LLPs) are commonly neglected in event generators used for LLP searches, potentially limiting the interpretation of experimental sensitivities. In this talk, we present spin-correlation effects in scenarios where LLPs are produced in pseudoscalar meson decays, such as $\pi^0,\eta,\eta^{\prime}\rightarrow AX\rightarrow Af\bar{f}$, with $X$ denoting the LLP. We report a consistent implementation of production-decay spin correlations within the FORESEE framework, extending its capabilities beyond the standard unpolarized case. Using the dark photon (DP) as a benchmark LLP, we show that spin correlations induce distinctive angular signatures in the final-state fermions. In particular, the cosine of the fermion polar angle, defined with respect to the beam axis in the DP rest frame, provides sensitivity to the LLP spin. We apply this framework to the FASER2, NA62, SHiP, and DUNE experiments, adopting conservative assumptions for angular reconstruction systematics. We obtain 95% CL exclusion limits in the coupling-mass plane, demonstrating the potential of current and future experiments not only to discover LLPs, but also to discriminate between polarized and unpolarized production scenarios. These results highlight the phenomenological importance and robustness of angular observables as complementary probes of new physics at the intensity frontier.

Speaker: Sebastián Julio Fuenzalida Garrido (Universidad Técnica Federico Santa María)

14:25 Minimal Non-Abelian Discrete 3HDMs with Neutrino Masses and Dark Matter Stability

We present minimal three-Higgs-doublet models (3HDMs) based on global non-Abelian
discrete symmetries that simultaneously explain neutrino masses and dark matter
stability. A residual $Z_2$ parity from the spontaneous breaking of the new
symmetry stabilizes the dark matter candidate, which runs in the loop generating
neutrino masses at one loop alongside a tree-level type-I seesaw contribution.
We identify $S_3$ and $D_4$ as the smallest non-Abelian groups realizing this
framework and determine the minimal models in both cases that are consistent with
current neutrino oscillation data. The resulting models conserve CP in both the
Yukawa and scalar sectors.

Speaker: Andres Layana-Ramirez (Universidad Católica del Norte)

14:50 Searching for the lepton-flavor violating γγeμ interaction at future e⁻e⁺ colliders

The discovery of charged lepton flavor violation (cLFV) would provide incontrovertible evidence for physics beyond the Standard Model. Among the various cLFV channels, photon-photon interactions offer a remarkably clean probe of electromagnetic phenomena. In this work, we explore the prospects of searching for the cLFV process $e^+ e^- \to e^+ e^- e \mu$ at future circular colliders (CEPC and FCC-ee). Adopting an effective field theory (EFT) framework, we investigate the $\gamma\gamma e \mu$ interaction generated by dimension-7 operators, ensuring consistency with stringent experimental limits from the $\mu \to e \gamma$ decay.
Leveraging the clean environment of $e^+ e^-$ collisions, we identify distinctive kinematic distributions—such as the transverse momentum of the scattered electron ($p_T^{(e^-\text{scattered})}$) and the central muon ($p_T^\mu$)—for efficient signal-background separation. By implementing a neural network classifier, we significantly enhance the sensitivity over traditional cut-based analyses. Our findings indicate that a $5\sigma$ discovery is attainable at the CEPC ($\sqrt{s} = 240$ GeV) with $3000\text{ fb}^{-1}$ and the FCC-ee ($\sqrt{s} = 350$ GeV) with just $200\text{ fb}^{-1}$, probing effective couplings down to $\mathcal{O}(10^{-10})$.

Speaker: Marcela Marin (Universidad de Antioquia)

15:15 Cabibbo-Kobayashi-Maskawa matrix phase from top-bottom quark components of bosons in a fermion basis, within the standard model

Within the CKM phenomenological matrix, the class of unmixed quarkfield
phase transformations to the top-bottom phase give around π/2. This
value is derived from 1) electroweak and heavy-quark mass connections [Phys.
Rev. D 99, 073001 (2019)] through the common Higgs operator, as the boson
fields’ discrete degrees of freedom can be equivalently represented in terms of the
fermions’, given Lorentz and gauge symmetries, and 2) a quantized formulation;
fixing the Higgs vacuum expectation value, top-bottom orthogonal consistent
configurations favor that phase value and mass hierarchy.

Speaker: Jaime Besprosvany (Instituto de Física, Universidad Nacional Autónoma de México)

15:40 MAGNETIC MONOPOLES PRODUCTION AND MASS LIMITS: THEORIES AND SEARCHES

The electric charge discrete nature has a prevalent role in the Dirac magnetic Monopole symmetrized Maxwell theory. Moreover hypothetical particles are overriding in several grand unified theories, and even connected with Berry geometric phase. Here theoretical proposals on magnetic Monopoles and related experimental searches are updated and compared. Our calculations aiming to obtain mass limits for different production mechanisms are presented, mainly Drell-Yan and Photon-Fusion of the Dirac magnetic Monopoles and Monopolium, in pp experiments for present and future colliders as LHC, HE-LHC, and FCC. Distinct theoretical frameworks proposed for 0,1/2, 1 spin angular momentum are addressed. Also distint masses ranges are explored considering ALICE, ATLAS, CMS and Moedal efforts, and perspectives.

Speaker: Beatriz Gay Ducati (IF-UFRGS)

14:00 → 16:30 Parallel Talks: Parallel Talks SD-802

14:00 The $\tau^- \to \pi^-\omega\nu_\tau$ Spectral function and its impact on $\tau^- \to \pi^-\pi^0\nu_\tau\gamma$

We describe the $\omega\pi$ spectral function, measured in the decay $\tau^- \to \pi^-\omega\nu_\tau$ by the CLEO Collaboration, using an importance sampling procedure to explicitly account for the correlation between the parameters of the corresponding form factor. We exhibit the improvement in the uncertainties, compared to the uncorrelated case, and show the agreement with the expected from the measurement of the cross section of $e^+e^- \to \omega\pi$ by SND experiment, which validates the conserved vector current (CVC) hipothesis. The generated data set of the parameters is used to compute the branching ratio of the decay, which is found to be consistent with the reported value by the PDG.
As an application, we consider the $\omega$-channel of the $\tau^- \to \pi^-\pi^0\nu_\tau\gamma$ process, the leading model dependent contribution in the vector meson dominance approach. We compute the contribution to the long distance electromagnetic correction function $G_{em}(t)$, of the pure $\omega$-channel and its interference with the structure independent part.
We show that the uncertainties using the set of correlated parameters are largely reduced with respect to the uncorrelated case. The implication on the isospin symmetry breaking correction to the muon magnetic dipole moment estimation from tau data is exhibited.

Speaker: Fabiola Fortuna (IFUNAM)

14:25 Cosmic Evolution of the Standard Model Flavor Charges

Since all the Standard Model (SM) parameters have been measured to precision at the percent level or smaller, one would aim to have a framework which describes baryogenesis as precise as possible, where the measured SM parameters are used as inputs. At high temperature before the electroweak symmetry breaking, the SM contains 15 approximate U(1) symmetries with the associated flavor charges. To describe the evolutions of these flavor charges in a flavor-basis-covariant manner such that physical observables are flavor-basis-independent, a total of five density matrices in flavor spaces are required: three for quarks and two for leptons. Taking into account the quantum chromodynamics and electroweak sphaleron interactions together with all the Yukawa interactions, we obtain the complete flavor-covariant Boltzmann equations. By imposing chemical equilibrium in the lepton sector, we further derive a new effective quark-flavor-covariant formalism which can be used when baryogenesis occurs through number asymmetry generation in the quark sector. To verify the consistency of this complete formalism, we first apply it to leptogenesis scenarios, reproducing previous results which utilize the effective lepton-flavor-covariant formalism up to small corrections due to the quark chemical equilibrium approximations used in the latter formalism. Then, for the first time, we apply the complete formalism as well as the effective quark-flavor-covariant formalism to a cloistered baryogenesis scenario where number asymmetries are generated in the quark sector, showcasing the good agreement between the results from the two formalisms. Finally, we release the first generic baryogenesis public code BOLEH (BaryOn and Lepton charge Evolution in the Hot big bang) where all the SM interactions are taken into account.

Speaker: Sergio Manuel Cubides Pérez (Universidade Federal do ABC)

14:50 Electroweak precision physics via angular distributions in τ decays to two pseudoscalars

Hadronic tau decays provide a unique low-energy laboratory for the charged-current interaction between quarks and leptons. Their use as an electroweak precision sector is, however, limited by nonperturbative QCD dynamics in the resonance region, encoded in hadronic form factors. In this work we show that angular information in two-hadron tau decays can be used to construct observables in which these form factors cancel, leading to first-principles Standard Model predictions up to light-quark-mass and radiative corrections. We derive the fully differential distributions for arbitrary two-pseudoscalar final states, including tau polarization, and extend them to the Weak Effective Field Theory at linear order in new-physics couplings. We then illustrate our strategy with several benchmark observables, for both unpolarized and polarized taus, whose Standard Model predictions can be obtained without modelling the dominant hadronic form factors and which receive characteristic beyond-the-Standard-Model corrections, in particular from tensor currents. These results provide concrete targets for Belle II, polarized-tau proposals such as Chiral Belle, and future high-statistics facilities, including super-tau-charm factories and FCC-ee, to test the electroweak structure of hadronic tau decays.

Speaker: Santiago Paz Castro (IFIC (CSIC-UV))

15:15 Model-independent Padé and D-Log Padé approximants for the hadronic contribution to the muon anomalous magnetic moment

The hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment, $a_\mu$, remains a key source of uncertainty in precision tests of the Standard Model. The MUonE experiment aims to determine this contribution through measurements of elastic electron–muon scattering, extracting the hadronic component of the running electromagnetic coupling in the spacelike region. However, the limited kinematic range accessible to the experiment requires a reliable extrapolation of the measured quantity over the full integration domain needed to determine $a_\mu^{\mathrm{HVP,LO}}$.

We investigate Padé and D-Log Padé approximants as systematic, model-independent tools for parametrizing and extrapolating the hadronic contribution. These methods exploit the analyticity properties of the underlying vacuum-polarization function to constrain its behavior beyond the directly accessible kinematic region. Their performance is assessed using pseudo-data generated from a model incorporating the expected statistical precision of MUonE. The analysis demonstrates how complementary rational-approximation strategies can provide controlled estimates of the HVP contribution, including conservative upper and lower bounds, while reducing reliance on external theoretical input. These results support the use of analyticity-based approximation methods in the extraction of the hadronic contribution to the muon anomalous magnetic moment and in the assessment of the precision attainable by MUonE.

Speaker: Camilo Alejandro Rojas Pacheco (Universidad de Ibague)

15:40 Pole parameters of the $f_2(1270)$ and $f_2'(1525)$ from a coupled-channel analysis of the radiative $J/\psi$ multipoles

We present a determination of the pole parameters of the tensor resonances $f_2(1270)$ and $f_2'(1525)$ through a combined analysis of hadronic scattering and radiative $J/\psi$ decay data. The fit includes the isoscalar $D$-wave $\pi\pi$ phase shift, the $\pi\pi\to K\bar K$ modulus, and BESIII data for $J/\psi\to\gamma\pi^0\pi^0$ and $\gamma K_SK_S$. For the radiative decays, we include all three $2^{++}$ multipoles, together with their relative phases. The radiative decay amplitudes are constructed using a coupled-channel Muskhelishvili–Omnès representation, accounting for inelastic two-body final-state interactions.

Speaker: David Alejandro Baron Ospina (Instituto de física corpuscular, IFIC, CSIC-UV)

14:00 → 16:30 Parallel Talks: Parallel Talks SD-803

14:00 Longitudinal Nuclear Suppression and Nonadditive Transport in Relativistic Heavy-Ion Collisions

We investigate longitudinal nuclear suppression in relativistic heavy-ion collisions using the observable (R_(dN⁄dy)), defined as the binary-collision-scaled ratio of rapidity distributions in Pb–Pb and p–p interactions. Numerical studies with EPOS, FTFP_BERT, and HIJING reveal notable model dependence: FTFP_BERT and HIJING reproduce the experimentally observed increase in the ratio toward forward and backward rapidities, whereas EPOS predicts qualitatively different behavior. Motivated by this discrepancy, we develop two analytical descriptions based on nonadditive statistics. First, starting from the Tsallis quasi-exponential distribution, we derive a closed analytical expression for the rapidity spectrum in terms of a hypergeometric function. Second, we formulate a transport approach based on the nonadditive Boltzmann equation in the relaxation-time approximation. The latter provides a satisfactory description of negatively charged pion data over the range \sqrt(s_NN)=6.3-17.3 GeV using physically admissible parameters. The extracted evolution of the nonadditivity parameter toward values above unity, together with t⁄τ of order one, indicates relaxation toward a non-Boltzmann power-law stationary state and supports the relevance of anomalous diffusion in the produced medium.

Speaker: Maciej Rybczyński (Jan Kochanowski University, Kielce, Poland)

14:25 Thermodynamical observables from multiplicity in Pb+Pb and Au+Au collisions

Using a statistical model, we analyze published multiplicity distributions for identified hadrons produced in heavy ion collisions in the energy range from 2.7-200 GeV. Our analysis enables the prediction of the multiplicity distributions for multi-strangeness hadrons that have not yet been measured in lower-
energy experiments. Furthermore, we obtain freeze-out parameters, including temperature, baryon chemical and strangeness potentials, the strangeness suppression factor, and the system radius, as functions of centrality and collision energy. Additionally, we computed and discussed the Skewness and its behavior
at lower collision energies, highlighting the importance of the freeze-out parameters in determining the liquid-gas phase transition in nuclear matter

Speaker: Eleazar Cuautle (Instituto de Ciencias Nucleares, UNAM)

14:50 Determination of data driven magnetic dipole moment of vector mesons

We present the first determination of the magnetic dipole moment of the $\rho$ and $K^*$ vector mesons, based on data from the BaBar Collaboration. We analyze the $e^{+} e^{-} \to \pi^+ \pi^- 2 \pi^0$ and $e^{+} e^{-} \to K^+ K^- 2 \pi^0$ processes which are sensitive to this parameter. We describe the $\gamma^* \to hadrons$ vertex using a vector meson dominance model, including the relevant intermediate resonant contributions. We find $\mu_\rho = 2.7 \pm 0.3 $ in $e/2 m_\rho$ units for the $\rho$ and $\mu_{K*} = 4.5 $ in $e/2 m_{K*}$ units. For this last, we stress the need for higher precision data to extract a more precise value of this parameter to confront it with theoretical predictions.

Speaker: Genaro Toledo (Instituto de Física, UNAM)

15:15 Intermittency and fractality in pp collisions at s = 7 TeV classified by the number of partonic interactions

High-multiplicity proton–proton collisions at the LHC exhibit collective signatures traditionally associated with quark–gluon plasma formation. To assess whether these signatures require a thermal medium, we analyze the fractal structure of phase space in $pp$ collisions at $\sqrt{s} = 7$ TeV simulated with PYTHIA 8.3, an event generator without hydrodynamics.

We use scaled factorial moments with the cumulant variable, classifying events by the number of multiple parton interactions rather than by multiplicity, which avoids the bias introduced when events are selected from the same phase-space region where the observable is measured.

The behaviour of the intermittency index as a function of the number of multiple parton interactions is discussed, together with the critical exponent of the Ginzburg–Landau formalism. A distinctive feature emerging in the class of a single partonic interaction is also presented.

Keywords: intermittency; scaled factorial moments; multiple parton interactions; Ginzburg–Landau; PYTHIA.

Speaker: Brayan Stiven Pardo Ruiz (Estudiante)

15:40 Generalized susceptibilities and the critical point of a van der Waals hadron resonance gas

The study of hadronic matter at high temperatures and baryon densities plays a central role in exploring the QCD phase diagram and the possible existence of a critical point. Generalized susceptibilities, which are related to cumulants experimentally accessible in heavy-ion collisions, are particularly sensitive to critical behavior and therefore valuable tools in this search. In this work, we use the hadron resonance gas (HRG) model with quantum van der Waals interactions, which contains a genuine critical point, and compare it with the ideal HRG using Thermal-FIST. We extract the chemical freeze-out line from STAR hadron yields and characterize the critical region: the critical point lies at T_c ≈ 19.5 MeV and μ_B ≈ 914 MeV. We then study the baryon, electric-charge and strangeness susceptibility ratios along the freeze-out line. We show how the critical signal depends on the distance between the freeze-out line and the critical point, and how it is affected when the baryon number is replaced by measurable proxies such as protons. Finally, we present a proposal for measuring strangeness-related susceptibility ratios in the MPD-NICA experiment.

Speaker: Rodrigo Garcia Formenti Mendieta (Instituto de Ciencias Nucleares, UNAM)

16:05 Novel Pade approximants and their application to Bjorken Sum Rule

Novel variants of Padé Approximants (PAs) are formulated specifically to reproduce the exact hierarchy of renormalon behavior within the Borel complex plane. This approach is fundamentally motivated by the appearance of branch cuts from Operator Product Expansion (OPE) contributions in Quantum Chromodynamics (QCD), which replace the isolated poles characteristic of large-nf limits. To resolve dominant cuts, the D-Log Padé approximant evaluates the logarithm, converting branch points into simple poles whose residues correspond to critical exponents; standard PAs are then used. To resolve deeper analytical structures, Confluent Padé Approximants (CPAs) target subdominant confluent singularities at a known singular position. Applying these rational approximants to the Bjorken Sum Rule yields precise, model-independent predictions for uncalculated higher-order coefficients in the perturbative series, with particular emphasis on the normalization of the leading and first subleading renormalon contributions.

Speaker: Cesar Ayala (Tarapaca University)

14:00 → 16:30 Parallel Talks: Parallel Talks SD-804

14:00 Design and Performance of a Triple-GEM Hodoscope for Cosmic Muon Tracking

We report on the design and operational characterization of a atmospheric cosmic-ray muon telescope employing two $10\times10\text{ cm}^2$ NA64-type triple-GEM detectors combined with a plastic scintillator coincidental trigger system readout via NIM electronics. Signal processing and data acquisition across the 1024 detector channels are performed synchronously with the trigger logic signal using the RD51 Scalable Readout System (SRS) equipped with the front-end ASIC VMM3a. Optimal operating conditions yield detection efficiencies up to $90\%$ and a time resolution of $9.9\pm 0.4\text{ ns}$. Angular distributions of the atmospheric muon flux measured under laboratory and open-sky conditions in Bogotá D.C., Colombia ($2600\text{ m}$ a.s.l.), were reconstructed. Upon acceptance and efficiency corrections, preliminar measurements of the flux exhibits a zenith dependence modulated by $\cos^n\theta$ ($n = 2.13\pm 0.5$) and vertical intensity $I_0 = 260\text{ m}^{-2}\text{ s}^{-1}\text{ sr}^{-1}$. Fluctuations observed in the angular distribution are attributed to acceptance correction errors under high electronic noise levels, along with clock distribution instabilities in the Clock and Trigger Fanout (CTF) board. Nevertheless, the physical parameters remain in agreement with historical measurements, confirming the feasibility of VMM3a--SRS integrated hodoscopes for atmospheric muon tracking.

Speaker: Santiago Meléndez (Universidad Nacional)

14:25 Cosmic-ray applications: muon and neutron techniques for volcanology and precision agriculture

Secondary cosmic-ray muons and neutrons carry information about the matter they traverse, making the natural cosmic-ray flux a free probe of the Earth’s surface. We present two applications developed within the Latin American Giant Observatory (LAGO). Both rely on the ARTI–MEIGA framework, which models the chain from the primary flux to the detector response at each site.
The first is volcano muography with MuTe 2.1, a portable hodoscope built at the Universidad Industrial de Santander for imaging the Cerro Machín volcano. It consists of two 60×60 cm² panels of 15×15 scintillator bars read out with WLS fibers and SiPMs. Its calibration validated the detector at three levels. Open-sky muon fluxes agree with ARTI predictions within ~18%. The ~30% attenuation measured with 0.5–3 cm lead absorbers is consistent with MEIGA simulations. Finally, a test muography of a nearby mountain reconstructed its topographic profile under field conditions.
The second is soil moisture estimation with cosmic-ray neutron sensing, which can bridge the gap between point sensors and satellites for plot-scale monitoring in precision agriculture. The N-ARTI chain couples CORSIKA and Geant4 to propagate neutrons into the soil. Continuous boundary conditions remove artificial flux losses of up to 98%, and validation against standalone CORSIKA shows discrepancies below 6%. The simulated epithermal flux follows the expected inverse dependence on soil moisture but lies 7–16% below the standard reference curve. This offset is attributed to soil mineralogy and shows that calibration must include local soil chemistry. In parallel, NaCl-doped water Cherenkov detectors enhance neutron capture, with simulations agreeing with measurements at different salt concentrations.
These results consolidate LAGO’s capability to translate cosmic-ray physics into validated tools for volcanology and precision agriculture.

Speaker: Christian Sarmiento Cano

14:50 GEANT4 Simulation of a Portable Scintillator-Cube/GEM Detector for Cosmic-Ray Muography

We present the design and GEANT4 Monte Carlo characterization
of a portable, modular cosmic-ray muon telescope intended for
small-to-medium-scale muography applications. The instrument combines
a segmented plastic-scintillator cube, arranged as an $N\times N\times N$
array of individually wrapped cells (default $N=3$, $50\times50\times50$
cm$^3$), with a single Gas Electron Multiplier (GEM) tracking plane
mounted below it at a variable stand-off distance. The full assembly is
mounted on a mechanically realistic aluminium support structure --
corner posts, a GEM-holder frame and a base plate -- that in turn
pivots, about a fixed floor stand, through an adjustable zenith angle,
so that the instrument's line of sight can be swept from the local
zenith to near-horizontal. We describe the GEANT4 implementation
of the geometry, materials and physics, the cosmic-ray primary
generator, and the ROOT-based data output used for per-hit
track reconstruction. We then present a feasibility study for using the
instrument in a muography configuration: a fixed, vertically-standing
target of standard rock (Particle Data Group definition, $\rho=2.65$
g/cm$^3$), sized to a Tusa-natural-pyramid-like scale $230$ m base,
$140$ m height, $400$ m stand-off), is introduced along the
telescope's line of sight, and the muon transmission through it is
obtained by comparing paired open-sky and with-target runs at matched
zenith angles. We discuss the geometrical and event-generation
methodology required for this comparison to be physically meaningful,
give analytic cross-checks of the expected rock path length and the
minimum surface muon energy needed to traverse it as a function of
zenith angle, and outline the full-statistics Monte Carlo campaign
needed to obtain a quantitative transmission curve.

Speaker: Alex Tapia (Universidad de Medellín)

15:15 Next-Generation of Power-over-Fiber for HEP Detectors and Advanced Physics Instrumentation

Power-over-Fiber (PoF) technology provides an alternative solution for delivering electrical power to electronics operating in harsh environments with high-voltage isolation requirements or electromagnetic interference. Recently, the novel application of PoF technology was successfully demonstrated for powering the Photon Detection System (PDS) of DUNE prototypes at CERN. Lessons learned from these deployments motivated the exploration of PoF systems operating at 1470 and 1550 nm.

This talk will summarize R&D results from the next generation of PoF technology, including the design and development of laser driver electronics, characterization of optical power delivery, optical-to-electrical power conversion efficiency, and evaluation of the response of silicon photomultipliers to these optical sources. These results will serve as the foundation for designing a PoF system capable of powering large-area photon detectors proposed for DUNE Phase II, as well as for potential applications in other research fields.

Speaker: David Martinez Caicedo (South Dakota Mines)

15:40 Lund Jet Plane tagger for boosted particles in the ATLAS experiment

This work presents the development, optimization, and deployment of a machine-learning-based jet tagger built upon the Lund Jet Plane representation within the ATLAS experiment at the Large Hadron Collider.

The central objective of this work is to investigate the viability of a Lund-plane-based framework for boosted-object tagging, with particular emphasis on its sensitivity to Monte Carlo modeling effects and jet mass correlations. The study includes a systematic characterization of generator-dependent variations using multiple parton shower and hadronization models, as well as the exploration of mitigation strategies such as mixed-generator training and phase-space restrictions in the declustering sequence.

The performance of the tagger is evaluated for boosted top-quark and W-boson identification and compared to established ATLAS constituent-based architectures, including graph neural networks and transformer-based models. While the Lund Plane tagger does not reach the highest background rejection achieved by state-of-the-art global-attention architectures, it demonstrates competitive performance across a broad transverse-momentum range, particularly at high pT, while relying on a physically structured and compact representation of the jet radiation pattern.

The implementation of the model within the ATLAS software framework (Athena) is also addressed. The tagger is adapted for ONNX-based inference and integrated into the Athena reconstruction chain, enabling its use within standard ATLAS analysis workflows.

An exploratory extension of the method to Higgs boson tagging is presented, establishing a consistent framework for evaluating Lund-plane-based approaches across multiple boosted-object topologies. Overall, this work provides a detailed study of the interplay between physics-motivated jet representations, machine learning architectures, and Monte Carlo modeling uncertainties in the context of modern ATLAS jet tagging.

Speaker: Mr Jean Pierre Cifuentes Salazar (Universidad Nacional de Colombia)

16:30 → 18:30 Posters & Empanadas

Wednesday, 2 December

09:00 → 09:45 Plenary Talk: Results from the LHCb Experiment

Convener: Prof. Diego Milanés (Universidad de Ingeniería y Tecnología - UTEC)

09:45 → 10:30 Plenary Talk: Theoretical perspectives on flavor physics

Convener: Prof. Yosef Nir (Weizmann Institute of Science)

10:30 → 11:00 Coffee Break

11:00 → 11:45 Plenary Talk: Low energy QCD and massive gluons

Convener: Prof. Marcela Peláez (Universidad de la República)

11:45 → 12:30 Plenary Talk: Results and perspectives from g-2 experiment

12:30 → 14:00 Lunch Break

14:00 → 17:30 Workshop: SILAFAE Laboratory Modules on Particle Detectors

Conveners: Prof. Carlos Avila (Universidad de los Andes) , Prof. Christian Sarmiento Cano

18:30 → 21:30 Conference Dinner

Convener: Carlos Andrés Florez Bustos (Universidad de los Andes)

Thursday, 3 December

09:00 → 09:45 Plenary Talk: Self Interacting Dark Matter Theory

Convener: Prof. Camilo García-Cely (Instituto de Física Corpuscular (IFIC)-UV/CSIC)

09:45 → 10:30 Plenary Talk: Results from The Light Dark Matter eXperiment (LDMX)

Convener: Prof. Cristina Mantilla (University of Virginia)

10:30 → 11:00 Coffee Break

11:00 → 11:45 Plenary Talk: BSM Physics Theory.

Convener: Prof. Myriam Mondragón

11:45 → 12:30 Plenary Talk: Vacuum Decay in the SM

Convener: Prof. José Ramón Espinosa (Instituto de Física Teórica (UAM-Madrid))

12:30 → 14:00 Lunch Break

14:00 → 16:30 Parallel Talks: Parallel Talks SD-704

14:00 SU(N) Baryon formation in the large N limit and Dark Matter

I discuss baryon formation in the early Universe in a confining SU(N) gauge theory containing quarks with masses well below the confinement scale and transforming in the fundamental representation of the gauge group. Assuming Casimir scaling of the confining potential between static SU(N) charges, I show that baryon formation is hindered by a Casimir bottleneck: for small quark clusters, which constitute the initial stages of N-quark baryon assembly, destruction processes greatly outweigh formation processes. Due to the large suppression in their relic number density, cosmologically stable SU(N) baryons can provide dark matter candidates with masses substantially larger than conventionally assumed.

Speaker: Enrico NARDI (INFN-LNF & NICPB, Tallinn)

14:25 Chiral dark matter

We explore the paradigm of "Chiral Dark Matter" based on minimal, anomaly-free gauge extensions of the Standard Model. We demonstrate how enforcing exact local anomaly cancellation in a secluded sector autonomously dictates the dark particle spectrum. Spontaneous symmetry breaking within this chiral framework naturally stabilizes the dark matter candidates.

Speaker: Diego Restrepo (Universidad de Antioquia)

14:50 Dark Neutrons as Dark Matter: Collisions in Halos and Direct Detection from Dark CP Violation

We consider confining gauge theories with a non-vanishing topological angle θ, which induces CP-violating interactions among dark pions and dark baryons, with dark matter consisting of dark neutrons. The θ term generates scalar pion--baryon couplings analogous to the CP-violating pion--nucleon interactions of QCD. These interactions give rise to an attractive long-range Yukawa potential mediated by the dark pions, whose strength is proportional to θ. Since the dark pions are naturally light pseudo-Goldstone bosons, the resulting force can lead to sizable dark matter self-interactions, providing a simple and theoretically motivated realization of the self-interacting dark matter paradigm. We also investigate the implications for direct detection in scenarios where the dark sector communicates with the Standard Model through a dark photon portal. The θ term induces dark electric dipole moments proportional to θ, which couple directly to the electric fields of nuclei and can substantially enhance direct detection rates. We show how the underlying interactions shape the recoil spectra and discuss the possibility of identifying the CP-violating origin of the signal through its time dependence. Finally, we analyze the interplay between dark matter self-interactions and direct detection signals, showing that both are controlled by the same CP-violating parameter. Our results demonstrate that the topological angle θ can play a central role in determining the phenomenology of composite dark matter.

Speaker: Giacomo Landini (LNF-INFN)

15:15 Effective Field Theory and Scalar Triplet Dark Matter

We discuss an extension of the standard model with a real scalar triplet, T, including non-renormalizable operators (NROs) up to d=6. If T is odd under a Z_2 symmetry, the neutral component of T is a good candidate for the dark matter (DM) of the universe. We calculate the relic density and constraints from direct and indirect detection on such a setup, concentrating on the differences with respect to the simple model for a DM T with only renormalizable interactions. Bosonic operators can change the relic density of the triplet drastically, opening up new parameter space for the model. Indirect detection constraints, on the other hand, rule out an interesting part of the allowed parameter space.

Speaker: Carolina Arbeláez Rodríguez (Universidad Técnica Federico Santa María)

15:40 Interacting scalar--fermion two-component dark matter in a gauged $U(1)_{B-L}$ model

We propose an interacting two-component dark matter model based on a gauged $U(1)_{B-L}$ extension of the Standard Model, which also accommodates neutrino masses through the type-I seesaw mechanism. The dark sector consists of a Dirac fermion $\chi$ and a complex scalar $S$, which can both be stable without imposing an additional discrete symmetry and are directly coupled by a gauge-invariant Yukawa interaction. The resulting conversion, semi-conversion, and semi-annihilation processes lead to a genuinely coupled freeze-out. After imposing collider and dark matter constraints, we identify viable solutions away from the $Z'$ resonance for both mass hierarchies, $m_S > m_\chi$ and $m_S < m_\chi$. Despite the strong direct-detection constraints, part of the surviving parameter space remains within the reach of next-generation experiments.

Speaker: CARLOS YAGUNA (UPTC)

14:00 → 16:30 Parallel Talks: Parallel Talks SD-716

14:00 Fermionic Dark Matter in a Scotogenic Model with a Complex Scalar Singlet

We study the phenomenology of the complex scoto-singlet model, an extension of the scotogenic framework that simultaneously accounts for radiative neutrino masses and fermionic dark matter. We perform a Markov Chain Monte Carlo scan of the parameter space, imposing theoretical consistency together with constraints from neutrino oscillation data, lepton-flavor violation, collider searches and the observed dark matter relic abundance. Viable dark matter solutions are found both near the Higgs resonance and in coannihilation regions, extending the allowed mass range with respect to the minimal scotogenic model. Direct- and indirect-detection signals are strongly suppressed, placing most of the viable parameter space beyond the reach of current experiments. At colliders, monojet searches offer the best prospects to probe our model in compressed-spectrum scenarios, while long-lived charged scalars may give rise to displaced or detector-stable signatures.

Speaker: Gustavo Ardila-Tafurth (Universidad de los Andes)

14:25 FIMP Dark Matter in Bulk Viscous Non-Standard Cosmologies

Feebly Interacting Massive Particles (FIMPs) provide a well-motivated dark matter scenario in which the observed relic abundance is generated through the freeze-in mechanism. Since this production takes place in the early universe, it can be significantly affected by non-standard cosmological histories, in which the expansion history prior to Big Bang nucleosynthesis is modified. In this work, we study FIMP dark matter production in a non-standard cosmology containing an additional field $\phi$ that decays into the Standard Model radiation bath and experiences dissipative processes described by a bulk viscous pressure within the Eckart formalism. We numerically solve the coupled evolution equations for the $\phi$ field, the thermal bath, and the dark matter number density, and compare the classical non-standard cosmology with its bulk viscous extension. We find that bulk viscosity enhances the energy density of the $\phi$ component and increases the subsequent entropy injection into the thermal bath, leading to a greater dilution of the FIMP abundance. As a consequence, new regions of the cosmological parameter space $(T_{\rm end},\kappa)$ and of the dark matter parameter space $(m_\chi,\langle\sigma v\rangle)$ can reproduce the observed relic abundance. These results illustrate how dissipative effects in the early universe, before Big Bang nucleosynthesis, can have significant implications for dark matter phenomenology.

Speaker: Rodrigo Salinas

14:50 FIMP dark matter in the scotogenic model at low-reheating temperatures

The scotogenic model offers an attractive framework that explains light neutrino masses while accommodating a viable dark matter candidate. In this work, we study the phenomenology of singlet fermion dark matter, $N_1$, produced via the freeze-in mechanism characterized by an instantaneous low reheating temperature, $T_{\text{rh}}$.
We explore the model's viable parameter space, incorporating current bounds from lepton flavor violation ($\mu \to e \gamma$) and direct detection limits. We show that low-reheating scenarios significantly reshape the viable region for $N_1$ dark matter, improving prospects for testing the scotogenic model in the FIMP scenario while keeping it consistent with current lepton flavor violation and cosmological bounds.

Speaker: Robinson Longas Bedoya (Institución Universitaria ITM)

15:15 ALP-Mediated Dark Matter at Low Reheating Temperature and the Belle II Excess

Belle II has reported a $2.7\sigma$ excess in $B^+\to K^+\nu\bar\nu$ over its Standard Model prediction, recently interpreted as arising from an axion-like particle mediating a thermal dark matter candidate. We reassess this interpretation using a new mass-differential measurement of the same data set and adding two visible-decay searches that earlier analyses omitted. The resulting bounds leave the predictions from a standard cosmological history only marginally compatible with the excess, viable in a narrow window of parameter space. Thus, we consider a situation where dark matter freezes out during a low-temperature reheating era, featuring entropy injection diluting the relic abundance, and lowering the couplings needed to match the observed dark matter density. This opens a region of parameter space that standard cosmology excludes, significantly improving the compatibility of the model with the Belle II excess.

Speaker: Joel Jones-Perez (Pontificia Universidad Católica del Perú (PUCP))

14:00 → 16:30 Parallel Talks: Parallel Talks SD-802

14:00 Scalarization of Reissner-Nordström Black Hole in Scalar-Torsion Teleparallel Gravity

In this work, we investigate the scalarization of the Reissner-Nordstr¨om black hole within a scalar-tensor teleparallel gravity framework. This approach enables a direct comparison between scalarization mechanisms induced by a scalar field nonminimally coupled to the torsion scalar and those resulting from its coupling to the electromagnetic invariant. We demonstrate the existence of distinct scalarized branches of solutions, classified by the number of nodes of the scalar field. These scalarized black hole solutions are asymptotically flat, and we analyze their thermodynamic properties.

Speaker: Joaquín Robledo

14:25 Charged Black Hole Binary Dynamics at Second Post-Minkowskian Order from Scattering Amplitudes

I will present the perspective of studying inspiral dynamics of electrically charged black hole binaries from scattering amplitudes in a quantum field theory. With this approach we obtain the conservative two-body Hamiltonian at second order in Newton's constant, while also incorporating the effects of the charge. Observables are derived thereafter.

Speaker: Allan Alonzo Artiles (IF-UNAM)

14:50 UV Finite Power Spectrum in a DFR-like Cosmological Spacetime

In this work, we present a model of gauge-invariant scalar perturbations of the metric and inflaton field within the framework of perturbative Algebraic Quantum Field Theory (pAQFT) on cosmological spacetimes, where we incorporate non-local effects motivated by a model of quantum spacetime based on non-commutative geometry, proposed in 1995 by Doplicher, Fredenhagen, and Roberts (DFR), by introducing non-local Gaussian kernels in the (n)-point functions of the gauge-invariant fields, described in terms of the Mukhanov–Sasaki variable and the Bardeen potentials.

We show that the primordial power spectrum of the Mukhanov–Sasaki variable, and consequently the corresponding curvature perturbations, is ultraviolet finite for inflationary and radiation-dominated backgrounds when the field is quantized in an adiabatic vacuum. Thus, the non-local effective theory provides a natural ultraviolet regularization, with the non-locality scale characterized by a parameter of the order of the Planck length.

Speaker: Juan Felipe Lopez Restrepo (Universidad de los Andes - Bogota)

15:15 Geometrical Foundations of BRST Quantization in Gauged Nonlinear Sigma Models and Beyond

We develop a geometric formulation of gauged nonlinear sigma models based on the coset target space $O(N+1)/O(N)$, emphasizing the interplay between target-space geometry and gauge symmetries. Using Killing vector fields, we construct the BRST transformations and investigate the geometric conditions underlying their nilpotency. We show how the closure of the Killing algebra provides a natural geometric interpretation of the BRST structure within the quantization framework. Finally, we examine representative realizations in electroweak chiral effective field theories and Skyrme-type models, exploring their implications for topological dark matter and physics beyond the Standard Model.

Speaker: Andres Castillo (Universidad Antonio Nariño)

15:40 Quantum Gravity: Entanglement of Black Holes

The relationship between quantum entanglement and spacetime geometry raises fundamental questions about gravitational interactions and information preservation in black holes. The AdS/CFT correspondence and the ER=EPR conjecture provide frameworks for exploring these connections and investigating the role of quantum correlations in the structure of spacetime.

This contribution presents a doctoral research proposal to investigate how quantum entanglement relates to geometric connectivity in black hole systems. The proposed approach combines the development of a mathematical model of the physical system with analytical calculations and computational simulations to compare configurations under controlled conditions.

Within the broader search for a quantum description of gravity, this work aims to clarify the role of entanglement in understanding gravitational interactions. Black holes provide the setting for examining how quantum correlations relate to spacetime geometry and how changes in entanglement may be associated with changes in geometric connectivity. By studying these connections, the project seeks to better understand the role of entanglement in the gravitational description of spacetime.

Speaker: Dr Julio Andres Florez Realpe (Universidad de Nariño)

14:00 → 16:30 Parallel Talks: Parallel Talks SD-803

14:00 Beyond w0 − wa and Phantom Crossing: Testing Models of Coupled Dark Sector

The combination of cosmic microwave background (CMB) measurements with distance measurements from baryon
acoustic oscillations (BAO) and type Ia supernovae (SNIa) suggests that dark energy is dynamical, with an equation of
state crossing the phantom divide at low redshifts. This feature can not be described within canonically normalized,
minimally coupled, self-interacting scalar field models. We investigate the possibility of achieving phantom crossing by
introducing an interaction in the dark sector such that the dark matter particle mass is dependent on the dark energy field
ϕ as $m \propto ϕ^{α}$
. We consider a self-interacting potential of the inverse power-law form $V \propto ϕ^{−β}$. We implement this model
both at the background and perturbative levels in a Boltzmann solver and use a bayesian framework to constrain its
parameters using using CMB, BAO and SNIa data. We find best-fits that have similar goodness-of-fits as the commonly
used phenomenological w0 − wa parameterization, providing a more fundamental understanding of the dark sector

Speaker: Rogerio Rosenfeld (IFT-UNESP & ICTP-SAIFR)

14:25 Gravitational Waves from Dimension-6 Assisted Peccei - Quinn Phase Transitions

We discuss a simple model-independent extension of the minimal KSVZ axion model, augmenting the Peccei - Quinn effective potential with a dimension-6 operator invariant under the Peccei - Quinn symmetry. We show that this operator can trigger a first-order phase transition and describe the following cosmological consequences. We map out the parameter space, consistent with present observational constraints, in which the phase transition produces a gravitational wave signal observable at current and future interferometers, and we elaborate on the resulting dark matter phenomenology. Finally, we present specific ultraviolet completions that generate the dimension-6 operator, each leading to distinct phenomenological signatures, which motivates our model-independent approach.

Speaker: Kristjan Muursepp (NICPB,Tallinn and INFN,Frascati)

14:50 Axion field inflation with non-minimal couplings, reheating and missalignment production

Axions are hipothetic particles proposed to solve the Strong CP problem in QCD. Yet, they are notable inflation and dark matter candidates. In this talk, we present a work were the radial axion component is the inflaton, whose perturbative decays produce radiation after inflation (reheating), and the angular part is dark matter produced through kinetic missalignment mechanism. The axion has a non-minimal coupling to gravity. We discuss constraints on the model parameters using inflationary observables, CMB potential signatures and dark matter abundance.

Speaker: Nicolás Gómez (INAOE)

15:15 Parameter space and mediator properties of a 2HDM+a portal to dark energy and dark matter

Cosmological data measure the dark-energy equation of state w at the percent level, but leave its microphysics largely undetermined, since distinct theories can reproduce the same expansion history. In the broad class of k-essence models, dark energy is a dynamical scalar with a non-canonical kinetic term, and the sound speed c_s² of its perturbations is what separates these theories, yet it remains essentially unconstrained. An approximate shift symmetry, which keeps the scalar light, allows it to interact with new particles only through derivatives. Through such interactions, c_s² would leave its imprint on the partial widths and branching ratios of a new pseudoscalar mediator, opening a possible collider window on dark-energy microphysics.

The framework is the two-Higgs-doublet model with a pseudoscalar mediator (2HDM+a), where the dark sector couples to a gauge-singlet pseudoscalar that mixes with the CP-odd state of the two Higgs doublets. This setup is a standard benchmark for dark-matter searches at the LHC and, in part of its parameter space, a candidate explanation of the excess observed near the top-quark threshold. Dark matter and dark energy would then communicate with the Standard Model through this common mediator, which inherits its couplings to quarks and leptons from the mixing. We map the regions of parameter space where this picture is viable under theoretical, electroweak-precision, and Higgs constraints, and show where dark energy reshapes the properties of the mediator. This provides the basis for future kinematic studies of the mediator’s visible and invisible decay patterns, aimed at disentangling potential dark-energy and dark-matter contributions at the LHC and the FCC.

Speaker: Cristian Fernando Rodriguez Cruz

14:00 → 16:30 Parallel Talks: Parallel Talks SD-804

14:00 Higher derivative corrections in String Supergravities

The effective action of string theory has a highly constrained structure due to the numerous symmetries of the underlying theory. Recently, a method known as the Generalized Bergshoeff-de Roo identification was developed, which benefit from diffeomorphism, Lorentz and gauge invariance, along with T-duality, to derive higher derivative couplings in the effective action within the framework of Double Field Theory. This method has been revisited and further refined to generate couplings directly within the standard Supergravity framework.

Speaker: Fabian Andres Portilla (Universidad del Cauca)

14:25 From A-hypergeometric systems to canonical differential equations for Feynman integrals using D-modules

Feynman integrals are fundamental building blocks of scattering amplitudes and correlation functions, and their efficient evaluation is essential for high-precision predictions at the Large Hadron Collider and for applications in gravitational wave physics and cosmology. A central challenge is the construction of manageable systems of differential equations, whose size can grow substantially with the complexity of the integral family. In this talk, we present a $D$-module framework that provides a systematically reduced description of these systems. By associating Feynman integrals in their Schwinger-parametric representation with Gel'fand--Kapranov--Zelevinsky (GKZ) hypergeometric systems, we construct Pfaffian systems whose dimension is controlled by the holonomic rank of the underlying $D$-module. For a range of one- and two-loop examples, we find that this dimension is no larger than the number of master integrals obtained through integration-by-parts (IBP) reduction, and is strictly smaller in several cases. The resulting systems can be transformed into canonical $\epsilon$-form, providing a direct route to the analytic structure and differential equations governing the integrals. These results demonstrate that $D$-module and GKZ methods can yield reduced differential systems for Feynman integrals and offer a complementary approach to the standard IBP framework.

Speaker: Mateo Jiménez Santacruz (Universidad Nacional de Colombia)

14:50 Conformal Journey through SUSY GUTs: From Finiteness to SUGRA Models

The Reduction of Couplings (RoC) method is a powerful theoretical tool for reducing free parameters in field theories. In Supersymmetric Grand Unified Theories (SUSY GUTs), it is critical for constructing all-loop finite models where beta functions vanish at every order. While previous applications successfully predicted the Higgs and third-generation quark masses by linking gauge and Yukawa sectors, the deeper symmetries of these models remain largely unexplored. This talk demonstrates how all-loop finite models exhibit a conformal regime driven by superpotential operators compatible with the RoC framework. Extending this to the soft-breaking sector, we assume the finite GUT is embedded within an effective $N = 1, d = 4$ Weyl-invariant SUGRA theory. Under this framework, we establish a direct connection between the RoC in the dimensionful SSB sector and the emergence of an anomaly-mediated (AMSB-like) pattern. This theoretical structure naturally leads to a specific formulation of the Kähler potential, aligning perfectly with the geometries studied in no-scale supergravity.

Speaker: Luis Enrique R. Rodríguez (Instituto de Física, UNAM)

15:15 Testing Zurek's scaling law in non-equilibrium lattice simulations

We present numerical results of a set of spin models with topological
charges, local topological defects or kinks. We study these defects
under rapid cooling, which takes the system out of thermal equilibrium,
decreasing the temperature from above to below its critical value.
This is a a toy study for the Kibble mechanism in the Early Universe,
which describes the formation of cosmic strings.
We are interested in the density of persisting defects, in excess
of the equilibrium density. Zurek predicted a scaling
law which relates this excess density to the cooling rate.
For a variety of models, types of defects and Monte Carlo algorithms,
such scaling laws with a single power are observed to high accuracy.
The exponents of these power laws, however, do not agree with
Zurek's conjecture.

Speaker: Wolfgang Bietenholz (Universidad Nacional Autónoma de México)

15:40 Profiles of cosmic strings for a gauged B-L symmetry

In the Standard Model, the difference between the baryon
number B and the lepton number L is conserved, which implies
an exact, global symmetry.
We turn it into a naturally exact, local symmetry by coupling
the quantum number B-L to an Abelian gauge field.
Gauge anomalies are cancelled by adding right-handed neutrinos
nu_R, which are not sterile. We arrange for a
nu_R-mass by adding a Higgs-type 1-component complex scalar
field. Thus we arrive at a modest but well-motivated
Standard Model extension.

We investigate the field equations in the corresponding extended
gauge-Higgs sector, involving both Higgs fields and the non-standard
U(1) gauge field. This leads to a set of coupled, non-linear
differential equations, which we solve numerically, focusing on
the structures of cosmic strings. For a variety of parameters,
we identify the string profiles and energy densities.
These profiles depend on the winding number of each of the Higgs
fields. As amazing peculiarities, we discover - for high winding
numbers - "overshooting" and "co-axial" solutions; in the latter
case, the profile of the standard Higgs field changes its sign
near the core of the cosmic string.

Speaker: Wolfgang Bietenholz (Universidad Nacional Autónoma de México)

16:30 → 17:00 Coffee Break

17:00 → 18:30 LAA-HECAP Meeting: 3rd General Assembly

Friday, 4 December

09:30 → 10:15 Plenary Talk: PPD and Interdisciplinary Applications

Convener: Prof. Carlos Avila (Universidad de los Andes)

10:15 → 11:00 Plenary Talk: Outreach in experimental HEP

Convener: Dr Dilia Portillo (TRIUMF)

11:00 → 11:30 Coffee Break

11:30 → 12:30 Closing and discussion

12:30 → 14:00 Lunch Break

14:00 → 15:30 CONHEP General Meeting