4th ComHEP: Colombian Meeting on High Energy Physics (Barranquilla, Colombia)

2 Dec 2019, 08:00 → 6 Dec 2019, 19:00 America/Bogota

Teatrino 1 (Centro Cultural, Universidad del Atlántico)

Alexander Moreno (Universidad Antonio Nariño), Carlos Sandoval Usme (Universidad Antonio Narino (CO)), Diego Milanes Carreno (Universidad Nacional de Colombia (CO)), Eduardo Rojas (Universidad de Nariño), Gabriela Alejandra Navarro (Universidad Antonio Narino (CO)), Mario A Acero-Ortega (Universidad del Atlantico), Nicolás Bernal (Universidad Antonio Nariño), Oscar Alberto ZAPATA NOREÑA, Richard Beanvides

This is the fourth Colombian Meeting on High Energy Physics (4th ComHEP).  We hope to bring together young and senior particle physicists from Colombia and abroad, to discuss recent progress in particle physics, cosmology and related areas. The program of the meeting will address a broad range of topics, such as:

• Standard Model and beyond
• Neutrino physics 
• Hadron and flavor physics
• Dark matter
• Cosmology
• Cosmic rays
• Future experiments

The fourth edition of this meeting will be held from December 2 to 6, 2019, at the Universidad del Atlántico, Barranquilla, Colombia.

Financial support will be available to a limited number of students presenting a parallel talk or a poster. See the Registration Section for details.

There is no registration fee for this meeting.

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Invited Talks

• John Ellis (King's College London) - Beyond the Standard Model
• Rogério Rosenfeld (IFT-UNESP, ICTP-SAIFR, Brazil) - Cosmology
• Riccardo Sturani (International Institute of Physics, IIP, Brazil) - Gravitational Waves
• Andreas Albert (Boston University, USA) - Dark Matter at LHC
• Antonio Cárcamo (Universidad Federico Santa María, Chile) - Models of neutrino masses and lepton hierarchies
• Roberto Lineros (Universidad Católica del Norte, Chile) - Dark matter
• Wolfgang Bietenholz (ICN-UNAM, Mexico) - Lattice QCD
• David Martínez (South Dakota School of Mines and Technology, USA) - Reactor neutrinos

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Scientific Organizing Committee 

• Alexander Moreno (Universidad Antonio Nariño - Ibagué)
• Bobby Acharya (King's College London, UK- International Centre for Theoretical Physics, Italy)
• Bruno El-Bennich (Universidade Cruzeiro do Sul, Brazil)
• Carlos Andres Flórez Bustos (Universidad de los Andes)
• Carlos Ávila Bernal (Universidad de los Andes)
• Carlos Sandoval (Universidad Antonio Nariño)
• Diego Milanés (Universidad Nacional)
• Eduardo Rojas (Universidad de Nariño)
• Gabriela Alejandra Navarro (Universidad Antonio Nariño)
• Jairo Alexis Rodríguez López (Universidad Nacional)
• José David Ruíz (Universidad de Antioquia)
• Mario A. Acero Ortega (Universidad del Atlantico)
• Nicolás Bernal (Universidad Antonio Nariño)
• Oscar Alberto Zapata Noreña (Universidad de Antioquia)
• Richard Benavides (Instituto Tecnológico Metropolitano)

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Supporting Institutions

                                          

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COMHEP2019_flyerB.pdf

First bulletin_COMHEPIV.pdf

Second_bulletin_COMHEPIV.pdf

Third_bulletin_COMHEPIV.pdf

Useful Map of Barranquilla and surroundings (Including the venue)

Monday, 2 December

08:00 → 09:00 Registration

09:00 → 09:20 Opening

Speaker: Mario A Acero-Ortega (Universidad del Atlantico)

apertura_COMHEP2019_compressed.pdf

09:20 → 10:20 Perspectives in Particle Physics

https://vidyoportal.cern.ch/join/kueKFENNmpBd

Speaker: Jonathan R. Ellis (University of London (GB))

JECOMHEP2019.pdf

10:20 → 11:20 Gravitational Wave Astronomy

Speaker: Prof. Riccardo Sturani (International Institute of Physics)

sturani_ComHEP_19Dec2.pdf

11:20 → 11:50 Coffee Break

11:50 → 12:10 A non-universal $U(1)_{X}$ gauge extension to the MSSM

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.

Speaker: Mr Juan Sebastian Alvarado Galeano (Universidad Nacional de Colombia)

COMHEP_4.pdf

12:10 → 12:30 Effective Lagrangians for Lepton Flavor Violating interactions involving a boson

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.

Speaker: Ms Marcela Marín Ochoa (Cinvestav)

MMarin-LFV MMarin-talk.pdf

12:30 → 14:00 Lunch break

14:00 → 15:00 Searches for exotic signatures with the ATLAS detector

Speaker: Gabriela Alejandra Navarro (Universidad Antonio Narino (CO))

ComHep-talk_GNavarro.pdf

15:00 → 16:00 CMS Highlights

Speaker: Carlos Avila Bernal (Universidad de los Andes (CO))

COMHEP2019_C_Avila.pdf

COMHEP2019_C_Avila.pptx

16:00 → 16:30 Coffee break

16:30 → 16:50 Spontaneous Breaking and Flat directions in Supersymmetry

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.

Speaker: Diana Garcia Sandoval (Universidad Nacional de Colombia)

SUSY_SSB_and_flat_directions_Diana_Garcia.pdf

16:50 → 17:10 Constaints for a Z' boson with non-universal couplings in a supersimmetric model

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.

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

COMHEP_CED.pdf

17:10 → 17:30 General Solutions for minimal non-universal Z' gauge bosons

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.

Speaker: Dr Eduardo Rojas (Universidad de Antioquia)

Eduardo_Rojas.pdf

17:30 → 18:30 Welcome drink

Tuesday, 3 December

09:00 → 10:00 DUNE Highlights

Speaker: Deywis Moreno Lopez (Universidad Antonio Narino (CO))

DUNE_ComHEP2019.pdf

10:00 → 11:00 Neutrinos from reactors

Speaker: Prof. David Martinez (South Dakota School of Mines and Technology)

comhep-december2019-martinezcaicedo.pdf

11:00 → 11:30 Coffee break

11:30 → 12:00 Latest results from the NOvA experiment

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.

Speaker: Enrique Arrieta Diaz (Universidad del Magdalena)

COMHEP2019_Arrieta.pptx

12:00 → 12:20 Dark sectors from Dirac radiative neutrino masses

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.

Speaker: Prof. Diego Restrepo (Universidad de Antioquia)

dm_comhep_2019.pdf

12:20 → 14:00 Lunch break

14:00 → 15:00 Sequentially loop-generated pattern of quark and lepton masses in models with extended symmetries.

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.

Speaker: Antonio Enrique Cárcamo Hernández (Universidad Técnica Federico Santa María)

TalkAECHComHep2019.pdf

15:00 → 15:20 Study of the neutrino nature through cross sections in the Left-Right Symmetric Model.

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).

Speaker: Frank Bula Martinez (Universidad del Atlántico)

frank_COMHEP2019.pdf

15:20 → 15:40 Overspinning process in Kerr black holes

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.

Speaker: Ivan Vasquez (Universidad del Atlántico)

15:40 → 16:00 U(1)' coupling constant at low energies from heterotic orbifolds

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.

Speaker: Omar Pérez Figueroa (Instituto de Física, UNAM)

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

16:00 → 16:30 Coffee break

16:30 → 18:30 Colombian Network status

Convener: Carlos Sandoval Usme (Universidad Antonio Narino (CO))

16:30 Profesores Colombianos en el CERN

Speaker: Ms Johanna Resnick

Un profesor de secundaria al CERN.pdf

Un profesor de secundaria al CERN.pptx

16:50 Suratómica y la Red Colombiana de Altas Energías

Speaker: Ms Natalia Rivera

Suratómica_EN_12-19.pdf

17:10 LASF4RI update

Speaker: Diego Restrepo (Universidad de Antioquia)

LASF4RI

17:30 Red Colombiana de Altas Energías: Actualidad y Prospectos

Speaker: Carlos Sandoval Usme (Universidad Antonio Narino (CO))

Colombian_network_2020.pdf

17:50 Discusión

Speaker: Carlos Sandoval Usme (Universidad Antonio Narino (CO))

Wednesday, 4 December

09:00 → 10:00 CP violation in charm quark physics

Speaker: Mr Carlos Ramirez (Universidad de los Andes)

C_Ramirezp_cpv.pdf

10:00 → 11:00 Heavy Flavor measurements and production studies at CMS

Speaker: Jhovanny Andres Mejia Guisao (Universidad de Antioquia (CO))

ComHep_HeavyFlavor_JhovannyMejia.pdf

11:00 → 11:30 Coffee break

11:30 → 11:50 Measurement of B+ production cross sections in pp collisions a 13 TeV

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

Speaker: Manuel Rodriguez (Universidad de Antioquia)

MRodrigez_Seminario.pdf

11:50 → 12:10 A model independent study of CP violation in decays of charmed mesons to three-body final states

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 $D_{(s)}^+ \rightarrow K^- K^+ pi^+$.

Speaker: Sergio Jaimes Elles (Universidad Nacional de Colombia)

CPinCharm_SJaimes.pdf

12:10 → 12:30 Study of the B+c → [(ηc → pp ̄) μ+ νμ] decay

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.

Speaker: Santiago Gomez Arias

Presentation_COMHEP.pdf

12:30 → 14:00 Lunch break

14:00 → 15:00 Particle physics by means of lattice simulations

Speaker: Wolfgang Bietenholz (UNAM, Mexico)

Wolfgang_Barranquilla19b.pdf

15:00 → 15:20 Charged current 𝑏→𝑐𝜏𝜈¯𝜏 anomalies in a general 𝑊′ boson scenario

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.

Speaker: John Gomez (UdeA-ITM)

JGomez_ComHEP.pdf

15:20 → 15:40 Heavy quarks within the electroweak multiplet

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.

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

Barranquilla.pdf

16:00 → 19:00 Poster session

16:00 Dark matter in Inert Doublet Model with one scalar singlet and $U(1)_X$ gauge symmetry

he study of the abundance of dark matter is carried out in an extension of the standard model with an additional gauge symmetry $U(1)_X$. The considered extension includes two doublet and one complex singlet of scalar fields. The dark matter candidate arises from the second doublet scalar field meanwhile the singlet and first doublet scalar fields provide additional portals to the relic density. We also analyze in detail the stability of the dark matter candidate through the introduction of the discrete $Z_2$ symmetry or with the same gauge symmetry $U(1)_X$. We find constraints on the model parameter space which are in agreement with (i) the most up-to-date experimental results reported by CMS and ATLAS collaborations, namely, signal strengths $\mathcal{R}_{x\bar{x}}$; (ii) upper limit on WIMP-nucleon cross section imposed by XENON1T collaboration and (iii) upper limit on the production cross-section of a $Z^{\prime}$ gauge boson times the branching ratio of the $Z^{\prime}$ boson decaying into $\ell^-\ell^+$, with $\ell=e,\,\mu$. Subsequently these constraints are used to compute the relic density reported by the PLANCK collaboration and we find that also satisfy it. Considering all constraints, we find regions that include light, intermediate and heavy dark matter candidate mass.

Speaker: Marco Antonio Arroyo Ureña

16:05 Dependence of the Z-production via ep-DIS on the choice of the parameter Q^2 involved in the PDF´s

We discuss Z-production in Deep Inelastic Scattrering (DIS) e+p -> e+Z+X using the Parton Model (PM), in the context of the Standard Model (SM). In contrast to the Deep Inelastic ep -scattering (e+p -> e+X), where Q^2 the transferred momentum square is unique, in the case of boson production it depends upon the mechanism involved, that is related to the electroweak interaction. We present results for the total cross section rates for ep collissions with an electron energy of 60 GeV and the proton energy of 7 TeV , this energies are expected to be reached at LHeC. We use different assignments for Q^2; namely Q, Q´y s. We perform our calculations at NNLO by making use of the Calc-HEP package.

Speaker: Wendy Carolina Gonzalez Olivares (BUAP)

16:10 Flavor changing neutral currents beyond the Standard Model

Models beyond the standard model with extra scalars have been highly motived by the discobery ofthe Higgs boson. The two Higgs doublet model type III considers the most general case for the scalarpotential, allowing mixing between neutral CP-even and CP-odd scalars fields. This work presentsthe results of the study on the t -> c gamma, t -> c Z, and t -> c h_1 decays, where h_1 is the StandardModel Higgs boson. The neutral flavor changing is generated by top-charm-Higgs coupling givenby the Yukawa matrix.

Speaker: Ricardo Gaitan Lozano (Universidad Nacional Autónoma de México)

16:15 Study of IceCube high energy neutrinos excess using unstable dark matter

Recently the IceCube collaboration team reported an excess of 28 high energy neutrinos, which is well above the predicted number of the background events. A possible link between this neutrino signal and unstable dark matter has been suggested, namely, decay products of unstable weakly interacting massive particles making up the dark matter halo of our Milky Way galaxy may be responsible for this neutrino emission. In this work we set constraints on the lifetime of decaying dark matter candidates for a range of masses in order to our predictions to be consistent with IceCube data. Particularly, we focus in studying the excess of neutrinos due to decays of Dark Matter occurring at the galactic center of the Milky Way. In addition, we carried out numerical simulations by using publicly available CLUMPY code in order to generate the neutrino signal due to DM decays and to extract out the background coming from further galactic and extragalactic sources.

Speaker: Jessica Lopez (BUAP)

16:20 Majoron contribution to the invisible Higgs decays

Nowadays, neutrino oscillations and Higgs boson existence has been confirmed. On the other hand, the possibility of extended scalars sectors as well neutrino mass origin are broad areas of research. Majoron minimal model consider both topics, which adds a complex singlet to Standard Model, $\sigma = (f + \sigma^{0} + i J)/\sqrt{2}$ that carries a $B-L$ charge 2. The pseudoscalar majoron $J$, $f$ being the expectation value of $\sigma$, and $\sigma^0$ as the heavy CP-even majoron partner, are the new physics particles. In addition, three right-handed neutrinos are added, then, the Dirac and majorana neutrino mass term are allowed thanks to Higgs doublet and complex singlet, respectively. We are interested on the invisible Higgs decays probability to majorons and its posible detection in LHC.

Speaker: Moises Zeleny Mora (BUAP)

16:25 Low Energy Theorems and the Higgs boson.

Decayings that have a lepton flavor violation (LFV) are affected by the standard model (SM). However, from recent observations at the LHC, some limits have been found for these types of processes that show a change in flavor, up to a confidence level of 3𝜎. In particular, the process ℎ → 𝜏𝜇 seems to maintain a higher decay ratio (branching ratio) 𝐵𝑅 (ℎ → 𝜏𝜇) 𝐵𝑅𝜏𝜇, compared to other channels. In this work we study the width of decay Γ (ℎ → 𝜏𝜇) Γ𝜏𝜇 and 𝐵𝑅𝜏𝜇 for this decay. The specification of both parameters is made using the following premises: The theoretical framework is that of the SM, but considers the neutrinos with mass, Both, 't Hooft - Feyman, and Unitary gauges, are used in the calculation:, The Low Energy Theorems (LETs) technique is used to make the calculus to a one loop approach. In the end, the result obtained is contrasted with other results reported in the literature that have been performed using some other calculation techniques.

Speaker: Roberto García (BUAP)

16:30 Comparisson between a muon and a high energy tau particle as seen on IceCube detector array

We present a study of the possible traits that can help to determine the difference between a muon and a high energy tau article regarding their in-ice energy losses. The study consists on muons and tau particles simulated on the atmosphere with an array of different energies ranging from 1 TeV to 1 EeV, and propagated in air and in-ice using PROPOSAL (Monte-Carlo lepton propagator), we keep track of the catastrophic energy losses caused by the ionization, pair production, photonuclear interaction and bremsstrahlung. This gives us information about the behavior of the tracks of energy losses for both types of particles. There are differences in the fluctuations of energy losses, for tau particles there will be more fluctuations of dE/dx and this will be a start point for a future algorithm that classifies the tracks according to the particle type.

Speaker: Santiago Pena-Martinez (Universidad Nacional de Colombia)

16:35 The 3-3-1 economical model with right-handed neutrinos using SARAH tool

We analyzed the 3-3-1 economical model with right-handed neutrinos using the software SARAH, we show the analytical results are correct when we compare them with the literature, besides, we can build the vertices necessary to close the loops diagrams and explore the possibility of to have masses to one up-quark and two quarks-down types to radiative level.

Speaker: Mr Richard Benavides (ITM)

16:40 Non Abelian SQED4 in the null-plane gauge

We are going to study the non-abelian SQED4 on the null-pane coordinates. The constraint structure of the theory is analyzed and appropriated boundary conditions on the field are imposed to fix the hidden subset first class constraint which generated improper gauge transformations and obtain an unique inverse of the second class constraints.

Speaker: Mr German Ramos (Universidad de Nariño)

16:45 S.Q.E.D.2 on the null plane using Faddeev-Jackiw quantization

Half a century ago Dirac has proposed three different forms of relativistic dynamics depending on the types of surfaces where independent modes were initiated. The first possibility when a space-like surface is chosen ( instant form) has been used most frequently so far and is usually called equal-time quantization. The second choice is to the a surface of a single light wave (front form or null-plane ). The third possibility is to take a branch of hyperbolic surface (point form). In this paper we are going to study S.Q.E.D.2 on the null-plane and we will show that one of the first class constraints of the theory has a contribution provided by the scalar sector and in addition the theory have a second class constraint in the scalar sector which is manifest in the free case. It is not natural in the instant form. The Faddeev-Jackiw procedure for constrained system is applied to calculate the commutation relations of the theory.

Speaker: Mr German Ramos (Universidad de Nariño)

16:50 INFLATION MODELS AND ITS IMPLICATIONS

Although inflation theory modifies our understanding of the first fraction of a second in the history of the universe, when combined with the standard Big Bang theory it preserves all the successes of the previous theory and complements it. Scientific literature shows that it is not really a single theory, but that there are a multitude of scenarios with names such as old inflation, new inflation, chaotic inflation, among others. The new Data, specifically those from the Planck satellite, can put restrictions, and even discard some of them. This project consists of a review of the theories of single field slow roll inflation and its current state.

Speaker: Daniel Fernando Pulido Guzmán

16:55 Neutrino oscillations in perspective, what do we know?

Neutrino oscillations are one of the few physical evidences beyond the standard model. From Pontecorvo's idea of representing neutrinos as a linear combination of mass states, we want to review the formalism of neutrino oscillations in the image of the three known flavors to date.
With the confirmation of the oscillations, we're searching to describe the phenomenon of the neutrino oscillation of the mixing matrix PMNS, its role in the expressions of the (anti) neutrino state and the value of the oscillation parameters observed in the most important experiments.

Speaker: Paula Fonseca (UPTC)

17:00 THE ANOMALOUS MAGNETIC MOMENT OF THE MUON g - 2 IN THE STANDARD MODEL AND IN SOME OF ITS EXTENSIONS

The anomalous magnetic moment of the muon $ g - 2 $ is a very special quantity that reflects almost the entire spectrum of effects incorporated in the Standard Model (SM) of particles, in addition to being one of the quantities measured with greater precision. Currently there is a deviation of $ 3 - 4 \sigma $ between theory and experimental results, discrepancy that is waiting to be well established by current experiments such as muon $g - 2$ in Fermilab and J-PARC in Japan. We calculate the $g - 2$ of the muon, as it is also known, to a loop in quantum electrodynamics (QED), Then we will study some extensions of the standard model that may be sensitive to the theoretical value of the anomalous magnetic moment of the muon.

Speaker: Santiago Ballesteros Barrera (Universidad Pedagógica y Tecnológica de Colombia (UPTC))

17:05 ELECTROMAGNETIC PROPERTIES OF THE "GHOST PARTICLE".

Neutrinos are very interesting fundamental particles, interact very weakly and their masses are very small. In many extensions of the Standard Model neutrinos acquire electromagnetic properties through quantum loops effects, hence the study of neutrino electromagnetic interactions is a tool in the search of the fundamentals of particle physics. Neutrino electromagnetic properties can be used to distinguish Dirac and Majorana neutrinos and also gives a path to new physics beyond the standard model. The consequences of these properties affect the fields of science, such as astrophysics, since in certain circumstances, such as the core-collapse supernovae the influence of the electromagnetic properties of the neutrino must be considered.

Speaker: YHARON ANDRES JUNCA MOLANO (Universidad pedagógica y tecnológica de Colombia)

17:10 Estudio de la sensibilidad de la violación de simetría CP en los decaimientos + y -

Se presenta un estudio preliminar sobre la violación de la simetría CP en los decaimientos
, donde a partir de un Monte Carlo se hace una simulación de estos decaimientos en un
Dalitz Plot, y se realiza mediante el modelo Isobar un análisis de la amplitud para para los
decaimientos del y .

Speaker: Mr Andres Aponte (Universidad Distrital Francisco Jose de Caldas)

17:15 An approach to Dirac neutrino masses through the use of texture zeros

In this work, we consider some phenomenological consequences of having neutrinos with Dirac masses instead of Majorana masses as assumed in most of the current literature. In order to carry out this analysis, we propose new five-zero textures for the mass matrices of the leptonic sector. From our approach, we find new values for the neutrino masses in both, the normal and inverted hierarchy. These zero textures reproduce the $U_{pmns}$ mixing matrix and deliver relationships between the mixing angles and the leptonic sector masses.

Speaker: Prof. Yithsbey Lucas Giraldo Usuga

17:20 Superconformal invariance on finite supersymmetric grand unification theories

In the context of grand unification supersymmetric theories, we treated the properties of finite theories (finite on sense of his absence of UV divergences at any order in perturbative expansion) and his implementation to construct a model phenomenological viable and consistent with the supersymmetric version of the standard model (MSSM). One of the most interesting theoretical properties of these theories is the existence of a superconformal manifold generated by the operators of the finite theory in 3+1 space-time dimensions and $\mathcal{N}=1$, and the fact that these two characteristics (finiteness and superconformal invariance). To prove that affirmation we focus our attention on the renormalization group functions $\beta_{g}$, $\beta_y$ and $\gamma_i$, his relation with scale invariance and his role to identify generators of the superconformal manifold. This result is consistent with work of D. I. Kazakoz, in the case of $\mathcal{N}=4$.

Speaker: Mr Luis Enrique Reyes Rodríguez (Instituto de Física, UNAM)

17:25 The implementation of the Type III seesaw mechanism for neutrino masses in the context 2HDM

The seesaw mechanism has remained the most elegant scheme to explain the smallness of the neutrino masses without having to unnaturally fine tune the Yukawa couplings to arbitrary small values. In the so-called type-III seesaw, three triplet fermions under SU(2) are added to the standard model particle contents. Once these heavy leptons are integrated out from the theory, the dimension-5 Weinberg operator is generated. After electroweak symmetry breaking Majorana neutrino masses are generated from this operator. The smallness of the neutrino mass is explained by the largeness of the heavy fermion mass and without having to fine tune the Yukawa couplings to very small values.

Speaker: Mr Julian Steven Gutierrez (Universidad Nacional de Colombia)

17:30 CHARACTERIZATION OF PLANAR SENSORS BONDED TO RD53A READOUT CHIP FOR CMS PHASE 2 INNER TRACKER SYSTEM

One of the challenges of the CMS detector is to get a good and reliable data, hence it is
necessary to work with more versatile, more compact and resistance devices, so the CMS
collaboration scheduled from 2024 to mid-2026 an upgrade program called High-Luminosity
LHC (HL-LHC) Phase 2, CMS detector will have a completely new silicon tracking detector.
The work proposed is to carry out test beam studies of planar sensors exposed to a 120
GeV proton beam at FTBF (Fermilab Test Beam Facility) in order to analyse efficiency,
cluster size and hit resolution before and after radiation leading to choose an optimal
operation of these sensors.

Speaker: Alvaro Javier Guerrero Laos (University of Puerto Rico (PR))

17:35 Charm baryon spectroscopy with D0p and D+p final states at LHCb experiment

We study several Dp+c.c. and Dp+c.c. prompt systems, inclusively produced from
pp collisions at the LHCb experiment, in order to perform singly charmed hadron
spectroscopy studies. We have observed a structure near at the threshold on D0p
sample, and a hint of structure on D+p sample connected with its Isospin partner
on D0p. Measurements of their masses and widths are reported.

Speaker: Ignacio Alberto Monroy Canon (Universidad Nacional de Colombia (CO))

17:40 Measurement of the fragmentation fraction ratio fs/fu

Knowledge of the fragmentation fractions of ${B_{s}^{0}\left ( f_{s} \right )} $ hadron is essential for determining absolute branching fractions ($\beta$) of decays of these hadrons in various (rare) processes at the LHC. One example is the rare disintegration ${B_{s}^{0}\rightarrow u^{+}u^{-}}$ , this fragmentation process can not be reliably predicted because it is driven by strong dynamics in the non-perturbative regime. Thus fragmentation functions for the various hadron species must be determined experimentally. The precise knowledge of the fragmentation fractions, in the kinematic phase space accessed by the experiment, is an important ingredient in the measurement of B-hadron properties. The work is developed within the context of the ${B_{s}^{0}\rightarrow u^{+}u^{-}}$ analysis, where the ratio $f_{s}/f_{u}$ enters as a key function in the branching fraction measurement because of its ability to quantify the relative production rate of the ${B_{s}^{0}}$ with respect to ${B^{+}}$. So $f_{s}/f_{u}$ is crucial to achieve greater sensitivity in the search for physics beyond the standard model. The branching fractions of a large number of ${B^{0}}$ and ${B^{+}}$ decays have been measured with high precision in the factories of B (Bell, BABAR), but no branching fraction of ${B_{s}^{0}}$ with an accuracy high enough to be used as a normalization channel is known. In the poster we will show a few preliminary results essential for the calculation of $f_{s}/f_{u}$ at CMS experiment.

Speaker: Mr Diego Alexander Hernandez Castrillon (Universidad de Antioquia)

17:45 Alcance del modelo isobar en la desintegración de 3 cuerpos

En física de sabores pesados, las desintegraciones a tres cuerpos son ampliamente utilizadas en el estudio de la dinámica fuerte, así como en la extracción de fases fuertes y débiles, por ejemplo, medidas de violación CP. El modelo isobar, describe este tipo de desintegraciones como una suma de procesos de desintegración a dos cuerpos mediados por resonancias, pero deja por fuera efectos de la interacción fuerte a bajas energías como interacción de estado final y rescattering. La gran estadística alcanzada en los experimentos a día de hoy, motiva la construcción de modelos más complejos que tengan en cuenta los efectos mencionados. En este sentido, este trabajo busca exponer los problemas del modelo isobar y mostrar alternativas a este.

Speaker: Mr Juan Sebastian Ordoñez Soto (Universidad Nacional de Colombia)

17:50 Leptonic Decay of meson D

Theoretical study of the leptonic decay of the D-meson, where the bound state of the two quarks decays through a W, results in two leptons, the branching fractions are calculated having very similar results to the experimental data.

Speaker: Leidy Matilde Portilla Mantilla (Universidad de Pamplona)

17:55 CP sensitivity Dalitz plot analisis of the decay B2KsKK

I study the weak three-body decay $B^0 \rightarrow K^0_s K^+ K^-$ at the LHCb experiment (Large Hadron Collider beauty) in the LHC (Large Hadron Collider) at CERN (Conseil Européen pour la Recherche Nucléaire). We validate the current results from Run 1 (2010-2012) and study the expected results for Run 2 (2015-2018) and Run 3 (2021-). The simulation of the experimental conditions like the tagging (flavour of the $B^0$), the detector efficiency and the number of expected events will determine the sensitivity of the phase space density (Dalitz plot) to the isobar amplitudes for the many resonance modes in the three-body decay, expecting to determine the expected precision of the CP-violating asymmetries of the flavour specific modes.

Speaker: Rafael David Nunez Palacio (Universidad Nacional de Colombia (CO))

18:00 Massive neutrinos and fermion mass hierarchy in a non-universal $U(1)_{X}$ extension with an invisible axion

We present a non-universal $U(1)_{X}$ extension and an additional global anomala Peccei-Quinn (PQ) symmetry to the standard model (SM). The scheme proposed allow us to distinguish among fermion families without introducing additional discrete symmetries and generating the correct ansatz of mass matrix to obtain the fermionic mass spectrum in SM. The symmetry breakdown is performed by two scalar Higgs doublets and two scalar singlets, where one of these has the excitation associated with the axion-particle which turns out to be a candidate for dark matter. The exotic sector is composed of an invisible axion $a$, one up-type $T$ and two down-type $J^{1,2}$ heavy quarks, two heavy charged leptons $E,\mathcal{E}$ and one right-handed $\nu_{R}^{e,\mu,\tau}$ additional neutrino per family. In addition, the large energy scale associated with the spontaneously breaking (SSB) of the PQ-symmetry provides a solution to the strong CP-problem, also giving masses to the right neutrinos in such manner that the active neutrinos acquire $eV$-mass values due to the see-saw mechanism implementation. We comment on the implications of the proposed model with electroweak baryogenesis.

Speaker: Yadir Garnica (Universidad Nacional de Colombia)

18:00 → 19:00 Public seminar: Los diminutos mensajeros del universo

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

20:00 → 22:00 Social Dinner

Thursday, 5 December

09:00 → 10:00 Dark Matter: theory

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

2019-jul-lineros-comhep.pdf

10:00 → 11:00 Searches for Dark Matter at the LHC

Speaker: Andreas Albert (Boston University (US))

2019-12-05_comhep.pdf

11:00 → 11:30 Coffee break

11:30 → 11:50 A theoretical framework for multicomponent dark matter

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.

Speaker: Carlos E. Yaguna

yagunacomhep19.pdf

11:50 → 12:10 Computational approach to study particle dark matter

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.

Speaker: José Halim (Universidad Nacional Autónoma de México)

comhep4th_halim_v2.pdf

12:10 → 12:30 Vector Boson Fusion as a dark matter signature in simplified dark matter models with scalar mediators

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

Speaker: Andres Santiago Duque Escobar (Universidad de Antioquia)

VBFDM.pdf

12:30 → 14:00 Lunch break

14:00 → 15:00 Ultraviolet Freeze-in and Non-Standard Cosmologies

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.

Speaker: Nicolás Bernal (Universidad Antonio Nariño)

bernal.pdf

15:00 → 15:20 Higgs-nucleons coupling and the Direct Search for Dark Matter

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.

Speaker: Concepción Arellano Celiz (FCFM-BUAP)

15:20 → 15:40 Lensing convergence and anisotropic dark energy in galaxy redshift surveys

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.

Speaker: Dr Wilmar Cardona (Universidad del Valle)

15:40 → 16:10 Coffee break

16:10 → 17:10 Cosmology

Speaker: Rogerio Rosenfeld (UNESP - Universidade Estadual Paulista (BR))

ComHEP2019.pdf

17:10 → 17:30 Closing

Speaker: Carlos Sandoval Usme (Universidad Antonio Narino (CO))

closing.pdf

Friday, 6 December

09:00 → 19:00 Free Day