arXiv subjects

Abdel Pérez-Lorenzana

Publications and source records attributed to Abdel Pérez-Lorenzana.

36 records · Page 2Linked to original sources

arXiv2011

Cosmic Bose dark matter

Cold and hot dark matter (CDM, HDM) imprint distinctive effects on the cosmological observables, naturally, they are often thought to be made of different kinds of particles. However, we point out that CDM and HDM could share a common origin, a Bose-Einstein condensate emerging with two components. In this framework, the mass and temperature constraints on HDM contain fundamental information of CDM, but also, the critical temperature of condensation shall be larger than the HDM temperature. We discuss two scenarios: a gas made of bosons and a gas made of boson-antiboson pairs. We use some cosmological data surveys to test the idea and constrain the bosonic DM parameters, including a forecast for the Planck mission. We find that the bosonic DM picture is consistent with data in the first scenario, although, the second one might be increasingly interesting for future data surveys.

astro-ph.CO↗

arXiv2010

Left-right symmetric model with $μ\leftrightarrowτ$ symmetry

We analyze the leptonic sector in the left-right symmetric model dressed with a $(Z_{2})^{3}$ discrete symmetry which realizes, after weak spontaneous breaking, a small broken $μ\lraτ$ symmetry that is suggested to explain observable neutrino oscillation data. $μ\lraτ$ symmetry is broken at tree level in the effective neutrino mass matrix due to the mass difference $\widetilde{m}_τ\neq \widetilde{m}_μ$ in the diagonal Dirac mass terms, whereas all lepton mixings arise from a Majorana mass matrix. In the limit of a small breaking we determined $θ_{13}$, and the deviation from the maximal value of $θ_{ATM}$, in terms of the light neutrino hierarchy scale, $m_{3}$, and a single free parameter $h_{s}$ of the model.

hep-ph↗

arXiv2008

Softly broken $μ\leftrightarrowτ$ symmetry in the minimal see-saw model

Neutrino oscillations data indicates that neutrino mixings are consistent with an apparent $ν_μ- ν_τ$ exchange symmetry in neutrino mass matrix. We observe that in the mininimally extended standard model with the see-saw mechanism, one can impose $μ\leftrightarrowτ$ symmetry at the tree level on all Lagrangian terms, but for the mass difference among $μ$ and $τ$ leptons. In the absence of any new extra physics, this mass difference becomes the only source for the breaking of such a symmetry, which induces, via radiative corrections, small but predictable values for $θ_{13}$, and for the deviation of $θ_{ATM}$ from maximallity. In the CP conserving case, the predictions only depend on neutrino mass hierarchy and may provide a unique way to test for new physics with neutrino experiments.

hep-ph↗

arXiv2008

Unification of cosmological scalar fields

We present a model where early inflation and late accelerating expansion of the Universe are driven by the real and imaginary parts of a single complex scalar field, which we identified as inflaton and phantom field, respectively. This inflaton-phantom unification is protected by an internal SO(1,1) symmetry, with the two cosmological scalars appearing as the degrees of freedom of a sole fundamental representation. The unification symmetry allows to build successful potentials. We observe that our theory provides a matter-phantom duality, which transforms scalar matter cosmological solutions into phantom solutions and vice versa. We also suggest that a complete unification of all scalar fields of cosmological interest is yet possible under a similar footing.

astro-ph↗

arXiv2005

An Introduction to Extra Dimensions

Models that involve extra dimensions have introduced completely new ways of looking up on old problems in theoretical physics. The aim of the present notes is to provide a brief introduction to the many uses that extra dimensions have found over the last few years, mainly following an effective field theory point of view. Most parts of the discussion are devoted to models with flat extra dimensions, covering both theoretical and phenomenological aspects. We also discuss some of the new ideas for model building where extra dimensions may play a role, including symmetry breaking by diverse new and old mechanisms. Some interesting applications of these ideas are discussed over the notes, including models for neutrino masses and proton stability. The last part of this review addresses some aspects of warped extra dimensions, and graviton localization.

hep-ph↗

arXiv2004

An Introduction to the Brane World

The study of the so called brane world models has introduced completely new ways of looking up on standard problems in many areas of theoretical physics. Inspired in the recent developments of string theory, the Brane World picture involves the introduction of new extra dimensions beyond the four we see, which could either be compact or even open (infinite). The sole existence of those new dimensions may have non trivial observable effects in short distance gravity experiments, as well as in our understanding of the cosmology of the early Universe, among many other issues. The goal of the present notes is to provide a short introduction to some basic aspects of the Brane World models. The discussion includes models with flat compact extra dimensions, as well as the so called Randall-Sundrum models.

hep-ph↗

arXiv2003

Charge Asymmetry in the Brane World and Formation of Charged Black Holes

In theories with an infinite extra dimension, free particles localized on the brane can leak out to the extra space. We argue that if there were color confinement in the bulk, electrons would be more able to escape than quarks and than protons (which are composed states). Thus, this process generates an electric charge asymmetry on brane matter densities. A primordial charge asymmetry during Big Bang Nucleosynthesis era is predicted. We use current bounds on this and on electron disappearance to constrain the parameter space of these models. Although the generated asymmetry is generically small, it could be particularly enhanced on large densities as in astrophysical objects, like massive stars. We suggest the possibility that such accumulation of charge may be linked, upon supernova collapse, to the formation of a charged Black Hole and the generation of Gamma-Ray Bursts.

hep-ph↗

arXiv2002

Small Dirac Neutrino Masses and R-parity from Anomalous U(1) Symmetry

We suggest that many of the free parameters in the supersymmetric extensions of the Standard Model can be all linked together to the existence of a non universal U(1) gauge symmetry, which has been spontaneously broken at very high scale. Such a symmetry can easily generate, via non-renormalizable operators, appropriate tree level fermion mass textures as well as the $μ$-term of the Higgs potential. We give a general parametrization of those terms. As an output, R parity breaking terms only appear at a non-renormalizable level and linked to the Yukawa couplings, giving rise to the possibility of having an effective (exact) R parity conservation. As an interesting application of this idea we explore the case where neutrinos are Dirac particles. The scenario can be embedded in an extended SU(5) unification theory where the extra right handed neutrinos are introduced as singlets. Such theory has an exact R parity conservation and sneutrino as LSP.

hep-ph↗

arXiv2002

Baryogenesis in models with large extra dimensions

We describe how difficult it is to realise baryogenesis in models where the fundamental scale in nature is as low as TeV. The problem becomes even more challenging if we assume that there are only {\it two} extra compact spatial dimensions, because thermal history of such a Universe is strongly constrained by various cosmological and astrophysical bounds which translate the maximal temperature of the Universe which must not exceed $\sim {\cal O}(10)$MeV. This simply reiterates that the observed baryon asymmetry must be synthesised just above the nucleosynthesis scale. In this talk we address how to construct a simple model which can overcome this challenge.

hep-ph↗

arXiv2001

Baryogenesis in theories with large extra spatial dimensions

We describe a simple and predictive scenario for baryogenesis in theories with large extra dimensions which resembles Affleck-Dine baryogenesis. The Affleck-Dine field is a complex scalar field carrying a $U(1)_χ$ charge which is dynamically broken after the end of inflation. This generates an excess of $χ$ over $\bar χ$, which then decays into Standard Model fermions to produce an excess of baryons over anti-baryons. Our model is very constrained because the Affleck-Dine field has to be sufficiently flat during inflation. It is also a source for density fluctuations which can be tested in the coming satellite and balloon experiments.

hep-ph↗

arXiv2001

Assisted inflation via tachyon condensation

In this paper we propose a new mechanism of inflating the Universe with non-BPS $D4$ branes which decay into stable $D3$ branes via tachyon condensation. In a single brane scenario the tachyon potential is very steep and unable to support inflation. However if the universe lives in a stack of branes produced by a set of non-interacting unstable $\tilde {D4}$ branes, then the associated set of tachyons may drive inflation along our 3 spatial dimensions. After tachyon condensation the Universe is imagined to be filled with a set of parallel stable $D3$ branes. We study the scalar density perturbations and reheating within this setup.

hep-ph↗

arXiv2001

Affleck-Dine leptogenesis via right-handed sneutrino fields in a supersymmetric hybrid inflation model

The onset of inflation in hybrid models require fine tuning in the initial conditions. The inflaton field should have an initial value close to the Planck scale $M_{P}$, whereas the auxiliary "orthogonal" field must be close to zero with an extreme accuracy. This problem can be alleviated if the orthogonal field fastly decays into some states not coupled to the inflaton. Natural candidates for such states can be the right-handed neutrinos. We show that a non-trivial evolution of the classic sneutrino fields after inflation offers an interesting mechanism for generating a correct amount of lepton asymmetry, which being reprocessed by sphalerons can explain the observed baryon asymmetry of the Universe. Our scenario implies interesting bounds for the neutrino masses in the context of seesaw mechanism.

hep-ph↗

arXiv1999

GUTs and String-GUTs

We look for a connection between string theories and Grand Unified Theories (GUTs), with the aim to look for new insights in the existing four dimensional string-GUT problems. We argue that the construction of consistent string-GUT models could require the use of non canonical affine levels. We list the most common level values related to realistic GUTs.

hep-ph↗

arXiv1999

Minimal coupling and Feynman's proof

The non quantum relativistic version of the proof of Feynman for the Maxwell equations is discussed in a framework with a minimum number of hypotheses required. From the present point of view it is clear that the classical equations of motion corresponding to the gauge field interactions can be deduced from the minimal coupling rule, and we claim here resides the essence of the proof of Feynman.

quant-ph↗

arXiv1999

Exact solutions of n-level systems and gauge theories

We find a relationship between unitary transformations of the dynamics of quantum systems with time-dependent Hamiltonians and gauge theories. In particular, we show that the nonrelativistic dynamics of spin-$\frac12$ particles in a magnetic field $B^i (t)$ can be formulated in a natural way as an SU(2) gauge theory, with the magnetic field $B^i(t)$ playing the role of the gauge potential A^i. The present approach can also be applied to systems of n levels with time-dependent potentials, U(n) being the gauge group. This geometric interpretation provides a powerful method to find exact solutions of the Schrödinger equation. The root of the present approach rests in the Hermiticity property of the Hamiltonian operators involved. In addition, the relationship with true gauge symmetries of n-level quantum systems is discussed.

quant-ph↗

arXiv1999

An [SU(3)]^4 Supersymmetric grand unified model

We present a grand unified model based on the supersymmetric $SU(3)_L\otimes SU(3)_{CL}\otimes SU(3)_{CR}\otimes SU(3)_R$ gauge group, which unifies in one single step the three gauge couplings of the standard model at an scale $M\sim 10^{18}$ GeV, and spontaneously breaks down to $SU(3)_c\otimes U(1)_{EM}$ using only fundamental representations of SU(3). In this model the proton decay is highly suppressed and the doublet-triplet problem is lessened. The see-saw mechanism for the neutrinos is readily implemented with the use of an extra tiny mass sterile neutral particle for each generation which provides a natural explanation to the neutrino puzzle.

hep-ph↗

arXiv1999

Nonsupersymmetric gauge coupling unfication in [SU(6)]$^4\times$ Z$_4$ and proton stability

We systematically study the three family extension of the Pati-Salam gauge group with an anomaly-free single irreducible representation which contains the known quarks and leptons without mirror fermions. In the context of this model we implement the survival hypothesis, the modified horizontal survival hypothesis, and calculate the tree level masses for the gauge boson and fermion fields. We also use the extended survival hypothesis in order to calculate the mass scales using the renormalization group equation. The interacting Lagrangean with all the known and predicted gauge interactions is explicitly displayed. Finally the stability of the proton in this model is established.

hep-ph↗

arXiv1998

Non SUSY and SUSY one--step Unification

We explore the possibility of achieving one--step unification of the standard model coupling constants within non supersymmetric and supersymmetric gauge models, which at low energies have only the standard particle content. The constraints are the experimental values of $α_{em}$, $α_s$ and $\sin^2θ_W$ at $10^2 GeV$, and the lower bounds for FCNC and proton decay rates. The analysis is done in a model independent way.

hep-ph↗