arXiv subjects

A. Pérez-Lorenzana

Publications and source records attributed to A. Pérez-Lorenzana.

At least 19 recordsLinked to original sources

arXiv2025

Discrete Symmetries in the Chiral Fermion Formalism

In this paper, we present a revision of the discrete symmetries (C, P, T, CP, and CPT) within an approach that treats 2-component Weyl spinors as the fundamental building blocks. In particular, we show that we can define transformations for CP, T, and CPT without exchanging the right-handed and left-handed representative components that form a Dirac spinor, as is done in the traditional Dirac formalism. Then, we discuss some salient aspects of the discrete symmetries within quantum field theory (QFT). Besides the generic discussion, we also consider aspects arising within specific renormalizable theories, such as Quantum Electrodynamics (QED) and Yang-Mills (YM) theory. With the above, in addition to presenting a good introduction for non-experts, we establish how to use the chiral fermion formalism to study discrete symmetries in the context of QFT.

hep-th↗

arXiv2025

CPT Symmetry and Its Breaking in the Chiral Fermion Formalism

In this paper, we review the fundamental aspects of ${\cal N} = 1$ supergravity (SUGRA) and employ the chiral formalism to describe spin-$\frac{3}{2}$ fermions. Armed with this, we analyze the discrete symmetries of the graviton in the context of linearized gravity (LG) and Rarita-Schwinger (RS) fields, which include the description of the gravitino. Additionally, we highlight the advantages of the chiral formalism in classifying Lorentz and CPT-violating terms in RS theories, extending these models by including Lorentz-violating operators, as has been done in LG.

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arXiv2017

Effects of Lorentz invariance violation on cosmic ray photon emission and gamma ray decay processes

In this work, we use Lorentz invariance violation (LIV) introduced as a generic modification to particle dispersion relations to study some consequences of single photon emission, known as vacuum Cherenkov radiation, and photon decay processes in cosmic and gamma rays. These processes are forbidden in a Lorentz invariant theory but allowed under the hypothesis of LIV. We show that the emission rate have a dependency on the cosmic ray primary mass and the electric charge that could modify the UHECR spectrum. Furthermore, LIV dramatically enhances photon decay into an electro-positron pair above certain energy threshold. This last effect can then be used to set limits to the LIV energy scale from the direct observation of very high energy cosmic photon events by telescopes of gamma-rays.

astro-ph.HE↗

arXiv2017

Photon emission and decay from generic Lorentz Invariance Violation

One of the most studied approaches in phenomenology to introduce the breaking of Lorentz symmetry is the generic approach. This consist on the modification of the free particle dispersion relation by the addition of an extra power law term of order $n$ on energy or momentum. Using this approach in the photon sector, we have calculated the generic rates for vacuum Cherenkov radiation and photon decay, for any order $n$, at leading order. Explicit results for the decay and emission rates for the lowest values of $n$ are also presented.

hep-ph↗

arXiv2017

Restrictions from Lorentz invariance violation on cosmic ray propagation

Lorentz Invariance Violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same physical effects for vacuum Cherenkov radiation, as in some particular models with spontaneous breaking of Lorentz symmetry. This approximation is also implemented for the study of photon decay in vacuum, where stringent limits to the violation scale are derived from the direct observation of very high energy cosmic ray photon events on gamma telescopes. Photo production processes by cosmic ray primaries on photon background are also addressed, to show that Lorentz violation may turn off this attenuation process at energies above a well defined secondary threshold.

astro-ph.HE↗

arXiv2017

Implications of Lorentz symmetry violation on a 5D supersymmetric model

Field models with $n$ extra spatial dimensions have a larger $SO(1,3+n)$ Lorentz symmetry which is broken down to the standard $SO(1,3)$ four dimensional one by the compactification process. By considering Lorentz violating operators in a $5D$ supersymmetric Wess-Zumino mo\-del, which otherwise conserve the standard four dimensional Poincare invariance, we show that supersymmetry can be restored upon a simple deformation of the supersymmetric transformations. However, supersymmetry is not preserved in the effective $4D$ theory that arises after compactification when the $5D$ Lorentz violating operators do not preserve $Z_2: y\rightarrow -y$ bulk parity. Our mechanism unveils a possible connection among Lorentz violation and the Scherk-Schwarz mechanism. We also show that parity preserving models, on the other hand, do provide well defined supersymmetric KK models.

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arXiv2016

Vacuum Cherenkov radiation and photon decay rates from generic Lorentz Invariance Violation

Among the most studied approaches to introduce the breaking of Lorentz symmetry, the generic approach is one of the most frequently used for phenomenology, it converges on the modification of the free particle dispersion relation. Using this approach in the photon sector, we have calculated the squared probability amplitude for vacuum Cherenkov radiation and photon decay by correcting the QED coupling at tree level and first order in LIV parameters. For the lower order energy correction we calculate the emission and decay rate for each process.

astro-ph.HE↗

arXiv2014

The role of radiative corrections on an extradimensional SUSY model

Theories with extra-dimensional coordinates provide interesting mechanisms to achieve the rupture of symmetries. Here we present a novel alternative to the usual geometric considerations to achieve supersymmetric breaking for an extra-dimensional Wess-Zumino model. A supersymmetric model is constructed where the superpotential contains an effective supersymmetric non renormalizable operator, which generates, after compactification, the explicitly rupture of supersymmetry for the excited Kaluza-Klein excitations. The supersymmetry breaking is, in turn, communicated, by the radiatives corrections, to the zero mode.

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arXiv2011

Unification and mass spectrum in the minimal $B-L$ model

Gauging $B-L$ symmetry provides a simple realization of the seesaw mechanism in a naturally anomaly free extension to the MSSM gauge group, $SU(3)_c\times SU(2)_L\times U(1)_Y \times U(1)_{B-L}$. However, as we discuss in here, it turns out that the simplest $B-L$ extension of the MSSM may change some of the conceptions about the path for gauge unification as well as to affect the predicted spectrum of the supersymmetric particles at low energy. For instance, the coupling $g_{B-L}$ ended up to be smallest of all of them and the lightest gaugino is the one related to $B-L$. RGE also help to understand the spontaneous breaking of the $U(1)_{B-L}$ and the vacuum expectation value of the sneutrino at low energies, which occurs in this type of models.

hep-ph↗

arXiv2008

Radion stabilization from the vacuum on flat extra dimensions

Volume stabilization in models with flat extra dimension could follow from vacuum energy residing in the bulk when translational invariance is spontaneously broken. We study a simple toy model that exemplifies this mechanism which considers a massive scalar field with non trivial boundary conditions at the end points of the compact space, and includes contributions from brane and bulk cosmological constants. We perform our analysis in the conformal frame where the radion field, associated with volume variations, is defined, and present a general strategy for building stabilization potentials out of those ingredients. We also provide working examples for the interval and the $T^n/Z_2$ orbifold configuration.

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arXiv2006

Fixing the Solar Neutrino Parameters with Sterile Neutrinos

Neutrino mixing matrix appears to be close to bimaximal mixing, but for the solar mixing angle which is definitively smaller than forty five degrees. Whereas it seems quite easy to understand bimaximal mixing with the use of new global symmetries, as in models using $L_e - L_μ- L_τ$, understanding the about to eleven degrees of deviation in the observed solar angle seems less simple. We suggest that such a deviation could be due to a light sterile neutrino that mixes with the active sector. The mass scale needed to produce the effect has to be smaller than atmospheric scale, and it would introduce a new mass squared difference which should be smaller than the solar scale. We present a toy model that exemplifies these features.

hep-ph↗

arXiv2004

Sneutrino condensate as a candidate for the hot big bang cosmology

If inflationary paradigm is correct, then it must create conditions for the hot big bang model with all observed matter, baryons and the seed perturbations for the structure formation. In this paper we propose a scenario where the inflaton energy density is dumped into the bulk in a brane world setup, and all the required physical conditions are created by the right handed neutrino sector within supersymmetry. The scalar component of the right handed Majorana neutrino is responsible for generating the scale invariant fluctuations in the cosmic microwave background radiation, reheating the Universe at a temperature~$T_{rh}\leq 10^{9}$ GeV, and finally generating the lepton/baryon asymmetry, $n_{B}/s\sim 10^{-10}$, with no lepton/baryon isocurvature fluctuations.

hep-ph↗

arXiv2004

Sneutrino condensate source for density perturbations, leptogenesis and low reheat temperature

We bring together some known ingredients beyond the Standard Model physics which can explain the hot Big Bang model with the observed baryon asymmetry and also the fluctuations in the cosmic microwave background radiation with a minimal set of assumptions. We propose an interesting scenario where the inflaton energy density is dumped into an infinitely large extra dimension. Instead of the inflaton it is the right handed sneutrino condensate, which is acquiring non-zero vacuum expectation value during inflation, whose fluctuations are responsible for the density perturbations seen in the cosmic microwave background radiation with a spectral index $n_s\approx 1$. The decay of the condensate is explaining the reheating of the Universe with a temperature, $T_{rh}\leq 10^{9}$ GeV, and the baryon asymmetry of order one part in $10^{10}$ with no baryon-isocurvature fluctuations.

hep-ph↗

arXiv2004

Dumping inflaton energy density out of this world

We argue that a brane world with a warped, infinite extra dimension allows for the inflaton to decay into the bulk so that after inflation, the effective dark energy disappears from our brane. This is achieved by the redshifting of the decay products into infinity of the 5th dimension. As a consequence, all matter and CMB density perturbations could have their origin in the decay of a MSSM flat direction rather than the inflaton. We also discuss a string theoretical model where reheating after inflation may not affect the observable brane.

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arXiv2003

Radion Cosmology in Theories with Universal Extra Dimensions

We discuss cosmology of models with universal extra dimensions, where the Standard Model degrees of freedom live in a $4+n$ dimensional brane, with $n$ compact and small extra spatial dimensions. In these models, the simplest way to obtain the conventional 4-dimensional Planck scale starting with a low string scale is to have also some larger extra dimensions, where only gravity propagates. In such theories, dimensional reduction generically leads to at least two radion fields, one associated with the total volume of the extra spatial dimensions, and the other with the ratio of the sizes of small and large extra dimensions. In this paper, we discuss the impact of the radion fields on cosmology. We emphasize various aspects of radion physics such as radion coupling to the Standard Model fields, bare and dressed radion masses during inflation, dynamical stabilization of radions during and after inflation, radion decay life time and its late dominance in thermal history of the Universe as well as its quantum fluctuations during inflation. We argue that models where the radion plays the role of an inflaton or the inflaton is a brane scalar field, run into problems. We then present a successful inflation model with bulk scalar fields that seems to have all the desired properties. We also briefly discuss the possibility of radion as a cold dark matter candidate.

hep-ph↗

arXiv2003

Electric Charge Quantization and Extra Dimensions

In models with flat extra dimensions tiny Dirac neutrino masses can be generated via the coupling of four dimensional Standard Model fields to a higher dimensional fermion. Here we argue that, in spite of the Dirac nature of the neutrino, quantization of the electric charge can still be understood as a result of anomaly cancellation, charge conservation and naturalness requirements.

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arXiv2002

Angular Inflation from Supergravity

We study supergravity inflationary models where inflation is produced along the angular direction. For this we express the scalar component of a chiral superfield in terms of the radial and the angular components. We then express the supergravity potential in a form particularly simple for calculations involving polynomial expressions for the superpotential and Kahler potential. We show for a simple Polonyi model the angular direction may give rise to a stage of inflation when the radial field is fixed to its minimum. We obtain analytical expressions for all the relevant inflationary quantities and discuss the possibility of supersymmetry breaking in the radial direction while inflating by the angular component.

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arXiv2001

Small Active and Sterile Neutrino Masses from the TeV Scale

A new mechanism for understanding small neutrino masses using only simple new physics at the TeV scale is proposed. As an application, it is shown how it can naturally lead to the mass hierarchy of the so called bimaximal mixing in the case of three active neutrinos, or the (3+1) scenarios for sterile neutrinos, using only the $SU(2)_L$ quantum numbers of the particles.

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