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Title: Isovector-channel role of relativistic mean field models in the neutrino mean free path

Abstract

An improvement in the treatment of the isovector channel of relativistic mean field (RMF) models based on effective field theory (E-RMF) is suggested, by adding an isovector scalar ({delta}) meson and using a similar procedure to the one used by Horowitz and Piekarewicz to adjust the isovector-vector channel in order to achieve a softer density dependent symmetry energy of the nuclear matter at high density. Their effects on the equation of state (EOS) at high density and on the neutrino mean free path (NMFP) in neutron stars are discussed.

Authors:
; ;  [1]
  1. Departemen Fisika, FMIPA, Universitas Indonesia, Depok, 16424 (Indonesia)
Publication Date:
OSTI Identifier:
20771154
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 72; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.72.065801; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; DENSITY; EQUATIONS OF STATE; ISOVECTORS; MEAN FREE PATH; MEAN-FIELD THEORY; NEUTRINOS; NEUTRON STARS; NUCLEAR MATTER; QUANTUM FIELD THEORY; RELATIVISTIC RANGE; SCALAR MESONS; SCATTERING

Citation Formats

Sulaksono, A., Hutauruk, P.T.P., and Mart, T. Isovector-channel role of relativistic mean field models in the neutrino mean free path. United States: N. p., 2005. Web. doi:10.1103/PhysRevC.72.065801.
Sulaksono, A., Hutauruk, P.T.P., & Mart, T. Isovector-channel role of relativistic mean field models in the neutrino mean free path. United States. doi:10.1103/PhysRevC.72.065801.
Sulaksono, A., Hutauruk, P.T.P., and Mart, T. Thu . "Isovector-channel role of relativistic mean field models in the neutrino mean free path". United States. doi:10.1103/PhysRevC.72.065801.
@article{osti_20771154,
title = {Isovector-channel role of relativistic mean field models in the neutrino mean free path},
author = {Sulaksono, A. and Hutauruk, P.T.P. and Mart, T.},
abstractNote = {An improvement in the treatment of the isovector channel of relativistic mean field (RMF) models based on effective field theory (E-RMF) is suggested, by adding an isovector scalar ({delta}) meson and using a similar procedure to the one used by Horowitz and Piekarewicz to adjust the isovector-vector channel in order to achieve a softer density dependent symmetry energy of the nuclear matter at high density. Their effects on the equation of state (EOS) at high density and on the neutrino mean free path (NMFP) in neutron stars are discussed.},
doi = {10.1103/PhysRevC.72.065801},
journal = {Physical Review. C, Nuclear Physics},
number = 6,
volume = 72,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • The equation of state (EOS) of dense matter and neutrino mean free path (NMFP) in a neutron star have been studied by using relativistic mean field models motivated by effective field theory. It is found that the models predict too large proton fractions, although one of the models (G2) predicts an acceptable EOS. This is caused by the isovector terms. Except G2, the other two models predict anomalous NMFP's. In order to minimize the anomaly, besides an acceptable EOS, a large M* is favorable. A model with large M* retains the regularity in the NMFP even for a small neutronmore » fraction.« less
  • We study the properties of neutron stars involving antikaon condensation with three different models in the framework of relativistic mean field (RMF) approximation theory: the Glendenning-Moszkowski (GM) model, the Zimanyi-Moszkowski (ZM) model, and the hybrid derivative coupling (HD) model. We take the isovector-scalar ({delta}-meson) channel interaction into account in our calculations and find that large mass neutron stars with kaon condensation can exist if the kaon optical potential is appropriately weak. The {delta}-meson channel interaction has a significant influence on the property of neutron stars and the effects are a little different for the three models.
  • The nucleon mean free path is obtained based on the relativistic {sigma}-{omega} model, the thermofield dynamics and the relativistic Dirac-Brueckner-Hartree-Fock results which includes the important medium effects at finite temperature in nuclear matter. The temperature and density dependence of the nucleon self-energy in nuclear matter is derived from the effective Lagrangian taking diagrams up to fourth order into account. The calculated results of the nucleon mean free path at zero temperature are in good agreement with the experimental data in normal nuclear matter. {copyright} {ital 1997} {ital The American Physical Society}
  • An exact expression for the mean free path in a relativistic description of nuclear matter is given. Corrections due to the spatial nonlocality are calculated. While the latter play a significant role in giving reasonable values for the mean free path in nonrelativistic models, they have minor effects in the relativistic description of the nuclear matter mean field.
  • The instability of nuclear matter due to particle-hole excitation modes has been studied in the framework of several relativistic mean-field (RMF) models. It is found that both the longitudinal and the transversal modes depend sensitively on the parameter sets used. The important impact of the vector and vector-scalar nonlinear terms on the stability of both modes is demonstrated. Our finding corroborates the result of previous studies, namely that certain RMF models cannot be used in high-density applications. However, we show that for certain parameter sets of RMF models this shortcoming can be alleviated by adding these nonlinear terms.