arXiv subjects

Jaime Besprosvany

Publications and source records attributed to Jaime Besprosvany.

8 recordsLinked to original sources

arXiv2025

Heavy-quark mass relation from a standard-model boson operator representation in terms of fermions

The standard-model can be equivalently represented with its fields in a spin-extended basis, departing from fermion degrees of freedom. The common Higgs operator connects the electroweak and Yukawa sectors, restricting the top and bottom quark masses[Phys. Rev. D 99, 073001, 2019]. Using second quantization, within the heavy-particle sector, electroweak vectors, the Higgs field, and symmetry operators are expanded in terms of bilinear combinations of top and bottom quark operators, considering discrete degrees of freedom and chirality. This is interpreted as either a basis choice or as a description of composite models. The vacuum expectation value is calculated quantum mechanically, which relates to the common mass-generating scalar operator and it reproduces the vector and quark-doublet masses. This also links the corresponding scalar-vector and Yukawa vertices, and restricts the t- and b-quark masses in a hierarchy relation.

hep-ph↗

arXiv2022

Primordial gravitational waves spectrum in the interacting Bose-Einstein gas model

We study the evolution and power spectrum of primordial gravitational waves in the interactive Bose-Einstein gas model for dark energy, relevant, as it addresses the coincidence problem. The model is applied in the radiation, matter and dark-energy domination stages. The model introduces a scale factor associated to the radiation-matter transition which influences the gravitational spectrum. We focus on the impact of the free parameters on both the gravitational waves amplitude and its power-spectrum slope. For sets of parameters fitting Hubble's law, we show that the model's parameter for today's dark-matter energy density has a noticeable impact on such waves, while the others produce an indistinguishable effect. The feasibility of detecting such waves under present and future measurements is discussed.

gr-qc↗

arXiv2019

Observational constraints on the free parameters of an interacting Bose-Einstein gas as a dark-energy model

Dark energy is modelled by a Bose-Einstein gas of particles with an attractive interaction. It is coupled to cold dark matter, within a flat universe, for the late-expansion description, producing variations in particle-number densities. The model's parameters, and physical association, are: $Ω_{G0}$, $Ω_{m0}$, the dark-energy rest-mass energy density and the dark-matter term scaling as a mass term, respectively; $Ω_{i0}$, the self-interaction intensity; $x$, the energy exchange rate. Energy conservation relates such parameters. The Hubble equation omits $Ω_{G0}$, but also contains $h$, the present-day expansion rate of the flat Friedman--Lemâitre--Robertson--Walker metric, and $Ω_{b0}$, the baryon energy density, used as a prior. This results in the four effective chosen parameters $Ω_{b0}$, $h$, $Ω_{m0}$, $Ω_{i0}$, fit with the Hubble expansion rate $H(z)$, and data from its value today, near distance, and supernovas. We derive wide $1σ$ and $2σ$ likelihood regions compatible with definite positive total CDM and IBEG mass terms. Additionally, the best-fit value of parameter $x$ relieves the coincidence problem, and a second potential coincidence problem related to the choice of $Ω_{G0}$.

astro-ph.CO↗

arXiv2014

Coincidence problem within dark energy as a coupled self-interacting Bose-Einstein gas

A late accelerated expansion of the Universe is obtained from non-relativistic particles with a short-range attractive interaction, and low enough temperature to produce a Bose-Einstein condensate; by considering coupled dark-energy particles, energy is interchanged with dark matter, allowing it to describe recent acceleration by strengthening its effect. We show that for a sizable range of parameters, dark energy and dark matter evolve with similar energy densities, solving the coincidence problem, and in agreement with the luminosity distance vs redshift, derived from supernova data.

astro-ph.CO↗

arXiv2010

Accelerated expansion of a universe containing a self-interacting Bose-Einstein gas

Acceleration of the universe is obtained from a model of non-relativistic particles with a short-range attractive interaction, at low enough temperature to produce a Bose-Einstein condensate. Conditions are derived for negative-pressure behavior. In particular, we show that a phantom-accelerated regime at the beginning of the universe solves the horizon problem, consistently with nucleosynthesis.

astro-ph↗

arXiv2005

Exact solution for charged-particle propagation during a first-order electroweak phase transition with hypermagnetic fields

We obtain the exact solution of the Klein-Gordon equation describing the propagation of a particle in two regions of different constant magnetic field, separated by an infinite plane wall. The continuity of the wave function and of its derivative at the interface is satisfied when including evanescent-wave terms. We analyze solutions on truncated spaces and compare them with previously obtained approximate solutions. The findings of this work have applications in the problem of the propagation of particles in the presence of a bubble wall in the midsts of an electroweak phase transition, where the two regions separated by the wall are influenced by different (hyper)magnetic field strengths.

hep-ph↗

arXiv2003

Axial charge segregation and CP violation during the electroweak phase transition with hypermagnetic fields

We study the scattering of fermions off the true vacuum bubbles nucleated during a first order electroweak phase transition in the presence of a background hypermagnetic field. By considering the limit of an infinitely thin bubble wall, we derive and analytically solve the Dirac equation in three spatial dimensions for left and right chirality modes and compute reflection and transmission coefficients for the case when the fermions move from the symmetric toward the broken symmetry phase. Given the chiral nature of the fermion coupling with the background field in the symmetric phase, an axial asymmetry is generated during the scattering processes. This mechanism is thus shown to provide an additional source of CP violation within the standard model. We discuss possible implications for baryon number generation.

hep-ph↗

arXiv1994

Hard-core Final State Interaction Effects in Deep Inelastic Scattering

Hard-core final state interaction effects in the response function are investigated in the asymptotic limit of momentum transfer q->Infinity. A new treatment of the response is presented, which displays the relevant scattering contribution. A modification of the otherwise expected free response is obtained for Fermi and Bose systems and smearing of the condensate peak is shown in this limit. A comparison with other treatments of final state interactions is made.

cond-mat↗