arXiv subjects

Jacek Rozynek

Publications and source records attributed to Jacek Rozynek.

4 recordsLinked to original sources

arXiv2018

Nucleon properties inside compressed nuclear matter

In this work we show the modifications of nucleon mass and nucleon radius with the help of the extended Relativistic Mean Field (RMF) model. We argue that even small departures above nuclear equilibrium density with constant nucleon mass require an energy transfer from the repulsive mean field to the quarks forming nucleon massive bags in Nuclear Matter (NM), together with the decrease in the nucleon volume. The transfer, which is proportional to pressure and absent in a standard RMF approach, provides good values for nuclear compressibility, symmetry energy and its slope. Different courses of the Equation of State (EOS), which depend on the energy transfer, are considered.

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arXiv2016

Nonextensive Nambu Jona-Lasinio model of QCD matter revisited

We present a revisited version of the nonextensive QCD-based Nambu - Jona-Lasinio (NJL) model describing the behavior of strongly interacting matter proposed by us some time ago. As before, it is based on the nonextensive generalization of the Boltzmann-Gibbs (BG) statistical mechanics used in the NJL model to its nonextensive version based on Tsallis statistics, but this time it fulfils the basic requirements of thermodynamical consistency. Different ways in which this can be done, connected with different possible choices of the form of the corresponding nonextensive entropies, are presented and discussed in detail. The corresponding results are compared, discussed and confronted with previous findings.

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arXiv2013

Pressure Corrections to the Equation of State in the Nuclear Mean Field

We show the connection between stiffness of equation of state in a Relativistic Mean Field (RMF) of Nuclear Matter (NM) and the existence of a strong violation of longitudinal Momentum Sum Rule (MSR) in RMF for a finite pressure. The increasing pressure between nucleons starts to increase the ratio of nucleon Fermi to average single particle energy and according to the Hugenholtz-van Hove theorem valid for NM the MSR is broken. In order to satisfy that MSR we propose changes which modify the nucleon Parton Distribution Function (PDF) above a saturation density. The course of Equation o State in our modified RMF model is very close to semi-empirical estimation and to results obtained from extensive DBHF calculations with a Bonn A potential. Other features of the model includes a good values saturation properties including spin-orbit term. Specially the proper stiffness of EoS recently discussed in an application to compact and neutron stars is important when studying star properties (mass-radius constraint), especially the mass of "PSR J1614-2230" the most massive known neutron star, which rules out many soft equations of state including exotic matter. An admixture of additional hyperons are discussed in our approach.

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arXiv2009

Nonextensive critical effects in the Nambu--Jona-Lasinio model

The critical phenomena in strongly interaction matter are generally investigated using the mean-field model and are characterized by well defined critical exponents. However, such models provide only average properties of the corresponding order parameters and neglect altogether their possible fluctuations. Also the possible long range effect are neglected in the mean field approach. Here we investigate the critical behavior in the nonextensive version of the Nambu Jona-Lasinio model (NJL). It allows to account for such effects in a phenomenological way by means of a single parameter $q$, the nonextensivity parameter. In particular, we show how the nonextensive statistics influence the region of the critical temperature and chemical potential in the NJL mean field approach.

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