Opening

• Mario A Acero-Ortega (Universidad del Atlantico)

Room: Teatrino 1

Perspectives in Particle Physics

• Jonathan R. Ellis (University of London (GB))

Room: Teatrino 1 https://vidyoportal.cern.ch/join/kueKFENNmpBd

Gravitational Wave Astronomy

• Riccardo Sturani (International Institute of Physics)

Room: Teatrino 1

A non-universal $U(1)_{X}$ gauge extension to the MSSM

• Juan Sebastian Alvarado Galeano (Universidad Nacional de Colombia)

Room: Teatrino 1 We propose a supersymmetric extension of the anomaly-free and three families nonuniversal $U(1)$ model, with the inclusion of four Higgs doublets and four Higgs singlets. The quark sector is extended by adding three exotic quark singlets, while the lepton sector includes two exotic charged lepton singlets, three right-handed neutrinos and three sterile Majorana neutrinos to obtain the fermionic mass spectrum. By implementing an additional $\mathbb{Z}_2$ symmetry, the Yukawa coupling terms are suited in such a way that the fermion mass hierarchy is obtained without fine-tuning. The effective mass matrix for SM neutrinos is fitted to current neutrino oscillation data to check the consistency of the model with experimental evidence, obtaining that the normal-ordering scheme is preferred over the inverse ones. The electron and up, down and strange quarks are massless at tree level, but they get masses through radiative correction at one loop level coming from the sleptons and Higgsinos contributions. We show that the model predicts a like-Higgs SM mass at electroweak scale by using the VEV according to the symmetry breaking and fermion masses.

Effective Lagrangians for Lepton Flavor Violating interactions involving a boson

• Marcela Marín Ochoa (Cinvestav)

Room: Teatrino 1 We have developed the most general effective field theory describing LFV involving an additional boson ($\chi$) up to dimension four terms. The effective couplings are constrained using current upper limits on the branching fractions of the $L\rightarrow\ell\chi$ and $L$ to $3\ell$ decays. Within this setting, we examine the consequences on the electron and muon anomalous magnetic moments and on Higgs boson decays. We provide experimental signatures able to distinguish the spin and parity of the $\chi$ boson.

Searches for exotic signatures with the ATLAS detector

• Gabriela Alejandra Navarro (Universidad Antonio Narino (CO))

Room: Teatrino 1

CMS Highlights

• Carlos Avila Bernal (Universidad de los Andes (CO))

Room: Teatrino 1

Spontaneous Breaking and Flat directions in Supersymmetry

• Diana Garcia Sandoval (Universidad Nacional de Colombia)

Room: Teatrino 1 In order to reproduce the CMB density fluctuations, inflationary models require an inflaton scalar field $\phi$ such that the potential is sufficiently flat near $\phi=0$, and acquires a large curvature around the minimum. In supersymmetric models these flat directions appear naturally in the superpotentials, finding conditions on the fields so the $F$ and $D$ terms are zero. On the other hand, when supersymmetry is spontaneously broken, these directions gain a large enough curvature to produce the field oscillations required in the inflationary scenario. The supersymmetric formalism is constructed from a Super-poincaré symmetry group composed by a Poincaré Subgroup and a fermionic symmetry subgroup, and it's algebra is given by Coleman-Mandula and Haag-Lopuszanski Sohnius theorems. The representations on fields are obtained through the coset Super-Poincaré/Lorentz and the Lagrangians for scalar and vector fields can be constructed. Hereinafter, conditions for spontaneous breaking of Supersymmetry in the Wess-Zumino, O'Raifertaigh and Fayet-Illiopoulos models are analyzed in order to obtain the mass-spectra of the fields involved. Finally, two simple superpotentials for the inflaton are showed to fulfill asymptotic behaviour that could give rise to inflation.

Constaints for a Z' boson with non-universal couplings in a supersimmetric model

• Carlos Eduardo Diaz Jaramillo (Universidad Nacional de Colombia, sede Bogotá)

Room: Teatrino 1 We explored in a supersymetric extension to a $U(1)_{X}$ non-universal model (Phys. Rev. D 100, 055037) some features regarding the fermion mass hierarchy and the Higgs mass at tree level. The Z' boson included within the non-universal symmetry involves D-terms in the Lagrangian that can predict a $125$ GeV Higgs boson, avoiding the necessity of large radiative corrections. In the present work we discuss how this is possible. Additionally, we compare our results with CMS and ATLAS upper bounds on dilepton $l^+l^-$ and diboson $W^+W^-$ production and derive with it some constraints for the $Z'$ mass.

General Solutions for minimal non-universal Z' gauge bosons

• Eduardo Rojas (Universidad de Antioquia)

Room: Teatrino 1 By allowing gauge anomaly cancellation between fermions in different families we find nonuniversal solutions for Z' models with the same content of fermions of the standard model plus three right-handed neutrinos. We also impose constraints from the Yukawa interaction terms reducing the number of free paraméters. Our solutions contain as particular cases well-known models in the literature. As an application, we report a model which evades LHC constraints, flavor changing neutral currents and low energy constraints. Simultaneously, the model is able to explain the flavor anomalies in the Wilson coefficients C9(µ) and C10(µ) without modifying the corresponding Wilson coefficients for the first family. In our approach, this procedure is always possible for Z' masses smaller than ∼ 2.5 TeV.

DUNE Highlights

• Deywis Moreno Lopez (Universidad Antonio Narino (CO))

Room: Teatrino 1

Neutrinos from reactors

• David Martinez (South Dakota School of Mines and Technology)

Room: Teatrino 1

Latest results from the NOvA experiment

• Enrique Arrieta Diaz (Universidad del Magdalena)

Room: Teatrino 1 NOvA is a long-baseline experiment that uses the NuMI beam, at Fermilab, to study muon neutrino to electron neutrino oscillations. The experiment is located 14.6 mrad off the beam axis which allows access a narrow band of neutrino energies centered at 2 GeV. NOvA is a two-detector experiment with one located underground at Fermilab (Near Detector), and the other one located on the surface in northern Minnesota (Far Detector), 810 km away from Fermilab. The design of the two detectors is identical, varying only in their mass: 14 kton for the Far Detector, and 300 ton for the Near Detector. The experiment has made a 4.4σ-significant observation of electron neutrino appearance using 12.33×10^20 protons on target delivered to the Fermilab NuMI neutrino beamline. The experiment recorded 27 muon neutrino to electron neutrino candidates with a background of 10.3 and 102 muon neutrino to muon neutrino candidates. The new antineutrino data is combined with neutrino data to measure the oscillation parameters |Δm^2_32|=2.48+0.11−0.06×10−3 eV^2/c^4, sin^2θ_23=0.56+0.04−0.03 in the normal neutrino mass hierarchy and upper octant and excludes most values near δ_CP=π/2 for the inverted mass hierarchy by more than 3σ. The data favor the normal neutrino mass hierarchy by 1.9σ and θ_23 values in the upper octant by 1.6σ.

Dark sectors from Dirac radiative neutrino masses

• Diego Restrepo (Universidad de Antioquia)

Room: Teatrino 1 Dark sectors emerging from an extra Abelian gauge symmetry can be defined by the way in which Dirac neutrino masses are generated at the radiative level.

Sequentially loop-generated pattern of quark and lepton masses in models with extended symmetries.

• Antonio Enrique Cárcamo Hernández (Universidad Técnica Federico Santa María)

Room: Teatrino 1 I will discuss two models where SM fermion mass pattern is sequentially loop-generated. The first one is a nonrenormalizable model with minimal particle content, whereas the second one is an extension of the Inert Higgs doublet model (IDM) where the SM hierarchies are generated sequentially by radiative virtual corrections in a fully renormalisable way, i.e. without adding any non-renormalisable Yukawa terms or soft-breaking operators to the scalar potential. In particular, in that extended IDM, due to the presence of both continuous and discrete family symmetries, the top quark acquires a tree-level mass, lighter quarks and leptons get their masses at one- and two-loop order, while neutrino masses are generated at three-loop level. That extended IDM has a potential to explain the recently observed $R_{K}$ and $R_{K^{\ast }}$ anomalies, thanks to the non universal $U_{1X}$ assignments of the fermionic fields that yield non universal $Z^{\prime}$ couplings to fermions. Furthermore such extended IDM can accommodate the experimental measurements of the muon anomalous magnetic moment and dark matter relic density.

Study of the neutrino nature through cross sections in the Left-Right Symmetric Model.

• Frank Bula Martinez (Universidad del Atlántico)

Room: Teatrino 1 Neutrinos are elementary particles with spin ½. If neutrinos are different from their antiparticles, they would be Dirac particles, allowing process where the lepton number is conserved. Otherwise neutrinos would be Majorana particles, and some Non Standard processes, like the neutrinoless double beta decay , could occur. The nature of neutrinos is still to be determined and, in this study, the cross sections between neutrinos and antineutrinos is calculated, to see if there are differences for Majorana and Dirac neutrinos, in the framework of the Left-Right Symmetric Model (LRSM).

Overspinning process in Kerr black holes

• Ivan Vasquez (Universidad del Atlántico)

Room: Teatrino 1 It is shown that extremal and near-extremal Kerr black holes cannot be destroyed and obtain a naked singularity, in absorption processes where matter satisfies the null energy condition along the generators. This results rely on the calculation of second order corrections to the final mass of the black hole, in agreement with the weak cosmic censorship conjecture.

U(1)' coupling constant at low energies from heterotic orbifolds

• Omar Pérez Figueroa (Instituto de Física, UNAM)

Room: Teatrino 1 Extensions of the Standard Model include frequently an additional $\text{U}(1)$ gauge symmetry. Such scenarios are known as Z’ or dark photon models and are relevant to address issues such as the meta-stability of the Higgs vacuum, the nature of DM or the muon g-2 anomaly. In the context of $E_8\times E_8$ heterotic string compactifications, MSSM-like models with extra $\text{U}(1)$ can be found, so that Z’ models can be realized in the low energy limit. We study such string vacua, obtained from a $\mathbb{Z}_8$ toroidal orbifold compactification, and characterize the Z’ coupling at low energies under certain assumptions. We find Z' coupling values around 0.44-0.7 and argue that a sample model may have the required properties to stabilize the Higgs vacuum.

CP violation in charm quark physics

• Carlos Ramirez (Universidad de los Andes)

Room: Teatrino 1

Heavy Flavor measurements and production studies at CMS

• Jhovanny Andres Mejia Guisao (Universidad de Antioquia (CO))

Room: Teatrino 1

Measurement of B+ production cross sections in pp collisions a 13 TeV

• Manuel Rodriguez (Universidad de Antioquia)

Room: Teatrino 1 The B+meson total and differential cross sections, as a function of transverse momentum pT, are measured in pp collisions at center-of-mass energy s=13TeV, on the basis of a data sample collected by the CMS experiment in 2018, corresponding to an integrated luminosity of 61.3 fb-1. The measurement uses the exclusive decay channel B+J/K+with the J/psi decaying to a pair of muons. The results are compared with the results obtained by CMS in 2016

A model independent study of CP violation in decays of charmed mesons to three-body final states

• Sergio Jaimes Elles (Universidad Nacional de Colombia)

Room: Teatrino 1 CP violation arises on the Standard Model from the complex phase of the CKM matrix. Here the asymmetries for B meson decays are expected to be of the order of $10^{-1}$. For the charm system its expected to be much smaller, of the order of $10^{⁻4}-10^{-3}$. Measurements for B decays seem to be in accordance with SM expected values and recent measurements from the LHCb collaboration indicate that so does the D system. These asymmetries can be enhanced in New Physics models, providing a valuable test of the SM. Dalitz Plot analysis for the determination of CP violation on three-body decays has been used most commonly within the Isobar method to model intermediate states. As an alternative, other methods have been studied recently that adress the model dependence. In this work we propose an implementation of the Miranda Procedure on for the decays $D_{(s)}^+ \rightarrow K^- K^+ pi^+$.

Study of the B+c → [(ηc → pp ̄) μ+ νμ] decay

• Santiago Gomez Arias

Room: Teatrino 1 Lepton universality implies that vector bosons are coupled equally to the three families of leptons. This feature is implicit in the standard model which is our current model in particle physics. Lepton universality tests seek to find some anomaly. We are interested in perform a lepton universality test studying the decay B+c → [(ηc → pp ̄) l+ νl]. We have started studying the B+c → [(ηc → pp ̄) μ+ νμ] decay to subsequently measure its branching fraction. We are using data from the LHCb of the run 2 pp collision of the years 2016 and 2017.

Particle physics by means of lattice simulations

• Wolfgang Bietenholz (UNAM, Mexico)

Room: Teatrino 1

Charged current 𝑏→𝑐𝜏𝜈¯𝜏 anomalies in a general 𝑊′ boson scenario

• John Gomez (UdeA-ITM)

Room: Teatrino 1 The very recent experimental information obtained from Belle experiment, along with the one accumulated by the BABAR and LHCb experiments have shown the existence of anomalies in the ratios R(D) and R(D∗) associated with the charged current transition b→cτν¯τ. We present a phenomenological study of parameter space allowed by the new experimental b→cτν¯τ data and with the mono-tau signature pp→τhX+MET at the LHC. For comparison, we include some of the W′ boson NP realizations that have already been studied in the literature.

Heavy quarks within the electroweak multiplet

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

Room: Teatrino 1 Standard-model fields and their associated electroweak Lagrangian are equivalently expressed in a shared spin basis. The scalar-vector terms are written with scalar-operator components acting on quark-doublet elements, and shown to be parametrization-invariant. Such terms, and the t- and b-quark Yukawa terms are linked by the identification of the common mass-generating Higgs operating upon the other fields, after acquiring a vacuum expectation value $v$. Thus, the customary vector masses are related to the fermions', fixing the t-quark mass $m_t$ with the relation $m^2_t+m^2_b=v^2/2$ either for maximal hierarchy, or given the b-quark mass $m_b$. A sum rule is derived for all quark masses that generalizes this restriction. An interpretation follows that electroweak bosons and heavy quarks belong in a multiplet.

Public seminar: Los diminutos mensajeros del universo

• Roberto A. Lineros (Instituto de Física Corpuscular U.Valencia/CSIC)

Room: Teatrino 1

Dark Matter: theory

• Roberto A. Lineros (Instituto de Física Corpuscular U.Valencia/CSIC)

Room: Teatrino 1

Searches for Dark Matter at the LHC

• Andreas Albert (Boston University (US))

Room: Teatrino 1

A theoretical framework for multicomponent dark matter

• Carlos E. Yaguna

Room: Teatrino 1 We show that a single $Z_N$ symmetry, which may be a remnant of a spontaneously broken $U(1)$ gauge symmetry, allows to simultaneously stabilize several dark matter particles. We systematically study scenarios with various scalar fields charged under a $Z_N$ and find that it is possible to get two ($N\geq 4$), three ($N\geq 6$), four ($N\geq 8$), or even more dark matter (stable) particles. A generic feature of these models is that the number of stable particles is not determined by the model but depends on the relation between the masses of the different fields.

Computational approach to study particle dark matter

• José Halim (Universidad Nacional Autónoma de México)

Room: Teatrino 1 One of the current challenges in high energy physics is to find a candidate for dark matter, which is viable with all experimental observations and also provides an estimate for future experiments. A practical way to carry out this study is through the existing computer packages. In this talk we will explain the implementation of the packages to calculate observable quantities related to dark matter.

Vector Boson Fusion as a dark matter signature in simplified dark matter models with scalar mediators

• Andres Santiago Duque Escobar (Universidad de Antioquia)

Room: Teatrino 1 We study the characteristics of the vector boson fusion signature in simplified dark matter model with a scalar mediator. We develop a selection for searches at the LHC and show the possible exclusion reach of such a search

Ultraviolet Freeze-in and Non-Standard Cosmologies

• Nicolás Bernal (Universidad Antonio Nariño)

Room: Teatrino 1 A notable feature of UV freeze-in is that the relic density is strongly dependent on the highest temperatures of the thermal bath, and a common assumption is that the relevant 'highest temperature' should be the reheating temperature after inflation $𝑇_\text{RH}$. However, the temperature of the thermal bath can be significantly higher in certain scenarios, reaching a value denoted T max , a fact which is only apparent away from the instantaneous decay approximation. Interestingly, it has been shown that if the operators are of sufficiently high mass dimension then the dark matter abundance can be enhanced by a 'boost factor' depending on ($𝑇_\text{max}/𝑇_\text{RH}$) relative to naive estimates assuming instantaneous reheating. We highlight here that in non-standard cosmological histories the critical mass dimension of the operator above at which the instantaneous decay approximation breaks down, and the exponent of the boost factor, depend on the equation of state 𝜔 prior to reheating. We highlight four examples in which the dark matter abundance receives a significant enhancement in the context of gravitino dark matter, the moduli portal, the Higgs portal, and the spin-2 portal (as might arise in bimetric gravity models). We comment on the transition from kination domination to radiation domination as a motivated example of non-standard cosmologies.

Higgs-nucleons coupling and the Direct Search for Dark Matter

• Concepción Arellano Celiz (FCFM-BUAP)

Room: Teatrino 1 At tree-level the Higgs boson couplings with quarks through the Yukawa couples, which turn out to be quite small for the light valence quarks of the nucleons. We show that the effective Higgs-nucleon coupling can be described with a Dyson-Schwinger (DS) type equation, in analogy with the equations obeyed by the quark mass. There, the strong QCD effects can induce the generation of a dynamical quark mass even in the limit $m_{q} → 0$; similar effects can also induce an enhancement for the Higgs-nucleon coupling. One important application of this result is for dark matter ($\chi$) direct search, where one looks for the collision of dark matter with nucleons $\chi N \rightarrow \chi N$ . In many models such scattering amplitude is mediated by the Higgs boson, and in some cases it could even be the most important one. We analyze the cross section of the process $\chi N \rightarrow \chi N$ within the dark matter-Higgs portal scenario using the DS ansatz (DSa), and then compare our results with those obtained using the Form factor Technique. We find that DSa provides a convenient parametrization to analyze the Higgs-nucleon coupling, which takes into account the low- $p^2$ effects.

Lensing convergence and anisotropic dark energy in galaxy redshift surveys

• Wilmar Cardona (Universidad del Valle)

Room: Teatrino 1 Analyses of upcoming galaxy surveys will require careful modelling of relevant observables such as the power spectrum of galaxy counts in harmonic space Cℓ(z,z′). We investigate the impact of disregarding relevant relativistic effects by considering a model of dark energy including constant sound speed, constant equation of state w0, and anisotropic stress. Here we show that neglecting the effect of lensing convergence will lead to substantial shifts in cosmological parameters such as the galaxy bias b0, the value of the dark energy equation of state today w0, and the Hubble constant H0. Interestingly, neglecting the effect of lensing convergence in this kind of models results in shifting H0 downwards, something which could shed light on the current tension between local and CMB determinations of the Hubble constant.

Cosmology

• Rogerio Rosenfeld (UNESP - Universidade Estadual Paulista (BR))

Room: Teatrino 1

Closing

• Carlos Sandoval Usme (Universidad Antonio Narino (CO))

Room: Teatrino 1