Modification of the masses of the lightest neutral mesons in a hadronic medium under an external magnetic field

The effective masses of the neutral mesons in a hadronic medium and under an external magnetic field are evaluated as functions of the baryonic density and the field intensity. For this purpose, the meson polarization is evaluated in the one-loop approximation using a quantum hadrodynamics model which includes π, σ, ω, and ρ mesons. The propagators of the baryons include the full effect of the coupling to the magnetic field through their charges and their anomalous magnetic moments. Within the range of magnetic intensities considered here 1017 GFil: Aguirre, Ricardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentin

Chiral symmetry and strangeness content in nuclear physics parametrized by a medium dependent bag constant

Non-perturbative QCD vacuum effects at finite density are parametrized by means of a bag constant B. It is extracted from a Nambu-Jona-Lasinio model with two or three flavors. The parameter B is used in an effective bag-like model of baryons to study the nuclear phenomenology. We examine the nucleon structure and the thermodynamical properties of symmetric nuclear matter, particular attention is paid to the symmetry energy and to the eventual phase transition to deconfined quark matter. An alternative sketch of the binding mechanism of symmetric nuclear matter emerges within this approach. It is also found that the inclusion of strangeness content in B is crucial for an appropriate description.Facultad de Ciencias Exacta

Equation of state of hadronic matter with dibaryons in an effective quark model

The equation of state of symmetric nuclear matter with the inclusion of non-strange dibaryons is studied. We pay special attention to the existence of a dibaryon condensate at zero temperature. These calculations have been performed in an extended quark-meson coupling model with density-dependent parameters, which takes into account the finite size of nucleons and dibaryons. A first-order phase-transition to pure dibaryon matter has been found. The corresponding critical density is strongly dependent on the value of the dibaryon mass. The density behavior of the nucleon and dibaryon effective masses and confining volumes have also been discussed.Comment: 9 pages, LaTex, 3 Postscript figures, a misprint correcte

Hadronic matter under an external magnetic field: In-medium modification of the pion mass

The covariant propagator of a fermion with intrinsic magnetic moment interacting with a uniform external magnetic field is presented for finite temperature and baryonic density. The case of a scalar boson is also considered. The final expressions are given in terms of a four-dimensional momentum representation. These results, which take account of the full effect of the magnetic field, are used to evaluate the modification of the pion mass at zero temperature as a function of the density and the magnetic intensity. For this purpose a self-consistent calculation, including one- and two-pion vertices, is employed.Instituto de Física La PlataConsejo Nacional de Investigaciones Científicas y Técnica

Vacuum effects on the properties of nuclear matter under an external magnetic field

The effects of the Dirac sea of nucleons are investigated within a covariant model of the hadronic interaction. I extend the usual mean field approximation and present a procedure to deal with divergences which are proportional to polynomials on the magnetic field intensity. For this purpose a nucleon propagator is used which takes account of the full effect of the magnetic field as well as the presence of the anomalous magnetic moments of both protons and neutrons. I examine single-particle properties and bulk thermodynamical quantities and conclude that within a reasonable range of densities and magnetic intensities the effects found are moderate.Fil: Aguirre, Ricardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

Modification of the masses of the lightest neutral mesons in a hadronic medium under an external magnetic field

The effective masses of the neutral mesons in a hadronic medium and under an external magnetic field are evaluated as functions of the baryonic density and the field intensity. For this purpose, the meson polarization is evaluated in the one-loop approximation using a quantum hadrodynamics model which includes π, σ, ω, and ρ mesons. The propagators of the baryons include the full effect of the coupling to the magnetic field through their charges and their anomalous magnetic moments. Within the range of magnetic intensities considered here 1017 G, the dependence on B is moderate for the pion and the longitudinal component of the ω meson and negligible for the remaining mesons.Instituto de Física La Plat

Modification of the masses of the lightest neutral mesons in a hadronic medium under an external magnetic field

The effective masses of the neutral mesons in a hadronic medium and under an external magnetic field are evaluated as functions of the baryonic density and the field intensity. For this purpose, the meson polarization is evaluated in the one-loop approximation using a quantum hadrodynamics model which includes π, σ, ω, and ρ mesons. The propagators of the baryons include the full effect of the coupling to the magnetic field through their charges and their anomalous magnetic moments. Within the range of magnetic intensities considered here 1017 G, the dependence on B is moderate for the pion and the longitudinal component of the ω meson and negligible for the remaining mesons.Instituto de Física La Plat

Hadronic matter under an external magnetic field: In-medium modification of the pion mass

The covariant propagator of a fermion with intrinsic magnetic moment interacting with a uniform external magnetic field is presented for finite temperature and baryonic density. The case of a scalar boson is also considered. The final expressions are given in terms of a four-dimensional momentum representation. These results, which take account of the full effect of the magnetic field, are used to evaluate the modification of the pion mass at zero temperature as a function of the density and the magnetic intensity. For this purpose a self-consistent calculation, including one- and two-pion vertices, is employed.Instituto de Física La PlataConsejo Nacional de Investigaciones Científicas y Técnica

Resilient Average and Distortion Detection in Sensor Networks

In this paper a resilient sensor network is built in order to lessen the effects of a small portion of corrupted sensors when an aggregated result such as the average needs to be obtained. By examining the variance in sensor readings, a change in the pattern can be spotted and minimized in order to maintain a stable aggregated reading. Offset in sensors readings are also analyzed and compensated to help reduce a bias change in average. These two analytical techniques are later combined in Kalman filter to produce a smooth and resilient average given by the readings of individual sensors. In addition, principal components analysis is used to detect variations in the sensor network. Experiments are held using real sensors called MICAz, which are use to gather light measurements in a small area and display the light average generated in that area