Beyond Zero-Temperature: Moduli Fields, Thermal Corrections, and Dark Matter Production (Dark Matter)

• Diego Gallego (Universidad Pedagógica y Tecnológica de Colombia.)

Early matter-dominated epochs and non-standard cosmological scenarios are frequently motivated by top-down constructions and UV completions of beyond-Standard Model physics. Scalar fields, as natural extensions to the Standard Model of particles, provide a well-studied framework for exploring deviations from the concordance cosmological model and might play a crucial role in dark matter production - whether through direct decays or modifications to the universe's thermal history. Notably, moduli fields, ubiquitous in supergravity and superstring models, develop finite-temperature corrections to their dynamics, leading to significant cosmological imprints despite never reaching thermal equilibrium. In this talk, we review the general dynamics of scalar fields in cosmology, including finite-temperature effects, and present preliminary results derived from modified Boltzmann equations. By implementing numerical solutions for a toy model of direct production, we explicitly contrast the zero-temperature and finite-temperature regimes, highlighting their phenomenological implications.

Analysis of the cosmological evolution parameters, energy conditions, and linear matter perturbations of an exponential-type model in f(Q) gravity (Dark Matter)

• Ivan Vasquez

We analytically study cosmological evolution in a flat FLRW spacetime in the context of modified STEGR gravity or f(Q), using an exponential two-parameter model which represents a smooth perturbative expansion around the ΛCDM model. The cosmological analysis is carried out by calculating the Hubble parameter as a function of redshift, for selected values of the parameters. The Hubble parameter is obtained analytically by means of several approximations good enough to deviate slightly from the numerical solution. Several late-time cosmological parameters are computed, such as dark energy state parameter, deceleration parameter, and statefinder parameters. Additionally, we analyzed the behavior of the classical energy conditions WEC, SEC, NEC, and DEC for both the combination of matter and geometrical contribution and the geometrical contribution alone. Beyond the background level, linear matter perturbations are studied by calculating parameters relevant to structure growth and formation. The overall results indicate that the model may exhibit quintessence-like and phantom-like behavior and it also impacts the growth of structures in the universe by means of late-time contributions to clustering.

Electromagnetic Birefringence Signatures of Ultralight Axions in Pulsar Timing Arrays (Dark Matter)

• Andres Castillo (Universidad Antonio Nariño)

Axion-like particles (ALPs) can behave as a wave-like dark matter medium, and their interactions with photons may leave observable imprints in astrophysical environments. In this talk, I will show how pulsar arrays can act as sensitive detectors of ALP effects through birefringence signatures observed in polarimetric measurements. We use high-precision polarimetry data from the Parkes Pulsar Timing Array, the QUIJOTE (Q-U-I Joint TEnerife) experiment, and the European Pulsar Timing Array to search for signals of ALP-induced effects arising from their electromagnetic behavior. A combined analysis, taking into account stochastic fluctuations, allows us to derive strong constraints on the mass and electromagnetic interactions of ultralight ALPs. I will also discuss theoretical opportunities and future prospects for detecting these particles using pulsars located in galactic regions with enhanced dark matter densities.

Probing Higgs-Portal Dark Matter with VBF Signatures at the HL-LHC (Dark Matter)

• Cristian Rodriguez (Universidad de los Andes)

We investigate current and projected constraints on Higgs-portal dark matter (DM) models, focusing on both scalar and fermionic DM candidates, using vector boson fusion (VBF) production of the Higgs boson at the LHC. By analyzing the parameter space in the plane of DM mass versus the Higgs-DM coupling, we aim to reinterpret existing LHC VBF + MET searches to set bounds on the invisible Higgs decay channels. To this end, we perform simulations in *MadGraph5\_aMC\@NLO* under LHC conditions to compute cross sections for VBF Higgs production followed by invisible decays. Experimental efficiencies are estimated through a recast of public analyses targeting the process $pp \rightarrow jj + \text{MET}$. We then rescale the integrated luminosity to project the reach of the High-Luminosity LHC (HL-LHC), identifying both currently excluded regions and those potentially probed with 3 ab$^{-1}$. Our results provide updated exclusion contours and projections in the Higgs-portal to DM parameter space.

Agujeros Negros Primordiales: Una Ventana hacia el Enigma de la Materia Oscura. (Dark Matter)

• Diego Cancelado Medina (Universidad Pedagógica y Tecnológica de Colombia)

Los agujeros negros primordiales (PBH's) han resurgido como una alternativa atractiva ante la falta de detección directa de partículas de materia oscura convencionales como los WIMP's. En esta charla se presentará una revisión fenomenológica sobre la viabilidad de los PBH's como constituyentes de una fracción significativa de la materia oscura. Se abordarán los escenarios cosmológicos que permiten su formación, las restricciones observacionales más recientes, así como los rangos de masa permisibles bajo dichas restricciones. Además, se discutirán las perspectivas futuras que ofrecen los nuevos observatorios gravitacionales y ópticos para detectar señales indirectas asociadas a PBH's.

Electroweak Phase Transition in a $Z_6$-Symmetric Model with Scalar Singlet and Fermionic Dark Matter (Dark Matter)

• Daniel Ruiz Mejía (Universidad de Antioquia)

We investigate the nature of the electroweak phase transition (EWPT) in a minimal $Z_6$-symmetric extension of the Standard Model, featuring a fermionic dark matter candidate ($\psi_L,\psi_R$) and a real scalar singlet ($\phi$). Selecting benchmark points that satisfy both the observed dark matter relic density and direct detection constraints, we analyze whether the EWPT is first-order in this scenario. Our study demonstrates how specific parameter choices can enhance the strength of the phase transition, providing a starting point for electroweak baryogenesis and gravitational wave signatures.

Phenomenology of pion dark matter in a $\theta$-Vacuum (Dark Matter)

• Oscar Zapata

We revisit a recently proposed framework in which dark matter (DM) consists of pions originating from a strongly interacting hidden sector analogous to QCD. A non-vanishing topological theta angle plays a central role by inducing resonant number-changing interactions that can account for the observed DM relic abundance and yield velocity-dependent DM self-interactions. We investigate the coupling between the dark and visible sectors via a massive dark photon. This connection is crucial for understanding the thermal equilibrium, DM stability, and constraints from indirect detection. Our findings confirm this framework is a consistent and predictive model for DM.

Matrices de masa y mezcla de neutrinos en el modelo con dos dobletes de Higgs tipo III (Neutrinos)

• Julian Steven Gutierrez Saavedra (National University of Colombia)

En el contexto del Modelo con Dos Dobletes de Higgs tipo III (M2DH-III), se obtienen las expresiones analíticas exactas para las matrices de masa y de mezcla de los neutrinos ligeros activos, generadas mediante el Mecanismo See-Saw tipo I (MSS-I), introduciendo una simetría de sabor permutacional S3. Para ello, se construye inicialmente el lagrangiano de Yukawa extendido, incorporando el modelo de Majorana con el objetivo de implementar el MSS-I para la generación de masa de neutrinos. A partir de esta construcción, se deriva las matrices de masa correspondientes a los leptones cargados y a los neutrinos activos de Dirac, obteniendo expresiones analíticas exactas para los elementos de las distintas matrices de masa y mezcla en función de las masas de los leptones cargados, las diferencias de los cuadrados de las masas de los neutrinos y los parámetros de oscilación. Finalmente, utilizando estas expresiones y aplicando un método estadístico basado en la verosimilitud, se estiman los valores de las masas de los neutrinos ligeros de Dirac y de los ángulos de mezcla.

Modelo Froggatt-Nielsen Compuesto para la generación de masas de neutrinos (Neutrinos)

• Jaime Stiven Guzmán Guerrero (Instituto Balseiro)

Se presenta física más allá del Modelo Estándar de partículas a través de un modelo compuesto que incorpora el mecanismo de Froggatt-Nielsen, ofreciendo nuevas posibilidades para explicar el origen del sabor en el sector leptónico. Se analiza la interacción entre la composición parcial de los fermiones y una simetría horizontal $U(1)$ para describir las jerarquías de masas y los ángulos de mezcla de los neutrinos de tipo Dirac. A partir de suposiciones sobre patrones derivados de la jerarquía de masas, se propone una textura para la matriz de masas, considerando un esquema de ordenamiento normal y parametrizada mediante el ángulo de Cabibbo. Este modelo permite reproducir adecuadamente la matriz PMNS observada, además de predecir mezclas suprimidas para los leptones cargados. Las simulaciones numéricas realizadas confirman que el modelo propuesto es compatible con los datos experimentales, constituyendo un marco teórico viable para describir la física de los neutrinos y los leptones cargados.

Sensitivity of NOvA to invisible neutrino decay (Neutrinos)

• Mario A Acero (Universidad del Atlantico)

In the current era of high-precision measurements of neutrino oscillation parameters, both current and upcoming experiments provide powerful opportunities to probe physics beyond the Standard Model. One such avenue is the possibility of invisible neutrino decay, a scenario in which neutrinos decay into undetectable final states, leading to distortions in the observed oscillation patterns. In this talk, we present the early stages of a study aimed at evaluating the sensitivity of the NOvA experiment to invisible neutrino decay. This investigation explores how NOvA’s long-baseline configuration and accumulated data can constrain or reveal signatures of non-standard neutrino properties within the three-flavor oscillation framework.

Feasibility to probe the dynamical scotogenic model at the LHC (Dark Matter)

• Carlos Andres Florez Bustos (Universidad de los Andes (CO))

In this talk we present an variation of the Scotogenic Model, that extends the gauge group by a global U(1) symmetry, and a singlet scalar that induces Spontaneous Symmetry Breaking to explain the origin of both Majorana Masses and Lepton number violation. Then, we make a brief analysis of the compatible parameter space for both fermionic and scalar dark matter, which can be considered in a compressed mass spectrum between the lightest fermionic and scalar states. Then, we make an analysis of the behavior of the production cross section of the DM candidate particle, for both Drell-Yan and Vector Boson Fusion mechanisms and different compressed mass spectra scenarios, as a function of the mass and compare it with the latest results given by the ATLAS and CMS experiments to establish the detection feasibility of the model at the LHC.

Caracterización de fibras ópticas de un detector de partículas usando IA (Estado actual) (Neutrinos)

• Jorge Eduardo Ossa Sánchez (Universidad de Medellín, Estudiante Doctorado en Modelación y Computación Científica)

En el contexto del sistema de calibración del sensor de fotones del detector lejano del proyecto DUNE se requiere realizar la implementación de una tecnología innovadora llamada Power over Fiber la cual, a grandes rasgos, consiste en transmitir energía proporcionada por un láser de alta potencia a través de fibra óptica.  Para cumplir con este objetivo es necesario contar con fibras ópticas de muy alta calidad con el fin de optimizar el funcionamiento del proceso. Se pretende en este proyecto proporcionar elementos de juicio para decidir si una fibra óptica es elegible, o no, para ser utilizada en la línea de transmisión. Todo esto con base en la imagen de un corte transversal de dicha fibra y con la ayuda de una red neuronal, superando el déficit de muestras de entrenamiento con un riguroso preprocesamiento de las imágenes disponibles.

Simulation of two flavor neutrino oscillations on a quantum processor (Neutrinos)

• Mauricio Guevara (Universidad Distrital Francisco José de Caldas)

Classical simulations of neutrino oscillations faces multiple computational challenges such as simulating collective neutrino systems (e.g. inside of core collapse supernovae) and incorporating complex quantum effects (matter effects, quantum decoherence in a dense medium). These challenges can be overcome using quantum simulation as these can emulate different quantum systems rather than calculating their associated probabilities. In this talk, its presented the emulation of a two flavor neutrino oscillation system using a quantum processor. First, following the methodology presented in [1], a U3-gate is used to represent the basis change (Mass-Flavor) and then a S-gate to make the system evolve in time. Once the circuit is designed, its parameters are adjusted to fit the conditions for different situations/experiments (DUNE, KamLAND). Finally a comparison between theoretical solutions, an IBM Qiskit simulation (AerSimulator) and an IBM quantum processor (ibm\_sherbrooke) is shown. The comparison shows a maximum porcentual error of 7\%. [1] Argüelles, C. A., Jones, B. J. P. (2019). Neutrino oscillations in a quantum processor. Physical Review Research, 1(3).

Sub-GeV Fermion Dark Matter with Scalar Mediator (Dark Matter)

• Gustavo Adolfo Castrillon Yepes (University of Antioquia)

Sub-GeV dark matter has gained significant attention due to its experimental accessibility for both direct detection searches and neutrino studies. In this work, we present a theoretical model introducing two new bosonic particles beyond the Standard Model: a vector boson and a scalar boson. The model establishes two distinct interaction portals connecting these mediator particles with fermionic dark matter and the Standard Model sector, thereby expanding the range of possible coupling mechanisms. As a key result, we have identified a phenomenologically interesting region in the sub-GeV mass range whose features could be probed by high energy physics experiments.

Simplified dark matter model with novel Vector Boson Fusion signatures for searches at colliders (Dark Matter)

• Diego Ríos (UdeA)

We investigate the potential to search for dark matter within a simplified model that introduces a new scalar/vector resonance connecting the Standard Model (SM) to the dark sector composed by a Dirac fermionic dark matter particle. This mediator couples to SM vector bosons, including gluons, giving rise to novel Vector Boson Fusion (VBF) topologies. These allow for the exploration of such signatures at collider experiments. We analyze the constraints on the model’s Wilson coefficients and other parameters from direct and indirect detection experiments, as well as from measurements of the dark matter relic abundance.

Testing the (3+2) sterile neutrino scenario using the IceCube experiment. (Neutrinos)

• ALEXANDER Arguello Quiroga (Universidade Federal da Integração Latino-Americana)

This analysis studies the IceCube's ability to test, phenomenologically, the presence of sterile neutrinos states in the context of the 3+2 model. As the neutrino mass splitting ∆m²∼1eV² can distort the angular and energy distributions of reconstructed muon events at the scale of a few TeV, where IceCube detection is highly optimized, it is a great opportunity to test sterile neutrino scenarios. Some considerations are established, based on previous analyses, in order to get conservative and robust limits, and also to reduce the number of parameters that must be tested, any other way, due to the total number of parameters, testing all of them could be computationally demanding. To obtain limits on the (3+2) sterile neutrino parameter space, a χ² function was used to compare a one-year sample of reconstructed muon events collected by IceCube and the expected number of events.