Nuclear Theory·nucl-th

Tuesday·April 19, 2016

5 papers—1 primary·4 cross-listed

02
The eLSM at nonzero density
Francesco Giacosa🇵🇱
The extended Linear Sigma Model (eLSM) is an effective model of QCD which includes in the mesonic sector (pseudo)scalar and (axial-)vector quarkonia mesons as well as one dilaton/glueball field and in the baryonic sector the nucleon doublet and its chiral partner in the mirror assignment. The chiral partner of the pion turns out to be the resonance $f_{0} (1370),$ which is then predominantly a quarkonium state. As a consequence, $f_{0} (500)$ is predominately not a quarkonium state but a four-quark object and is at first not part of the model. Yet, $f_{0} (500)$ is important in the baryonic sector and affects nuclear matter saturation, the high-density behavior, and nucleon-nucleon scattering. In these proceedings, we show how to enlarge the two-flavour version of the eLSM in order to include the four-quark field $f_{0} (500)$ in a chiral invariant manner. We then discuss homogeneous and inhomogeneous chiral restoration in a dense medium.
↳ hep-phnucl-thJ.Phys.Conf.Ser.(2016)·0 citations
03
Equation of state and transition temperatures in the quark-hadron hybrid model
Akihisa Miyahara🇯🇵 · Yuhei Torigoe🇯🇵 · Hiroaki Kouno🇯🇵 · Masanobu Yahiro🇯🇵
We analyze the equation of state of 2+1 flavor lattice QCD at zero baryon density by constructing the simple quark-hadron hybrid model that has both quark and hadron components simultaneously. We calculate hadron and quark contribution separately and parameterizing those to match with LQCD data. Lattice data on the equation of state are decomposed into hadron and quark components by using the model. The transition temperature is defined by the temperature at which the hadron component is equal to the quark one in the equation of state. The transition temperature thus obtained is about 215 MeV and somewhat higher than the chiral and the deconfinement pseudocritical temperatures defined by the temperature at which the susceptibility or the absolute value of the derivative of the order parameter with respect to temperature becomes maximum.
↳ hep-phhep-latnucl-thPRD(2016)·14 citations
04
Three-flavor chiral effective model with four baryonic multiplets within the mirror assignment
L. Olbrich🇩🇪 · M. Zétényi🇭🇺 · F. Giacosa🇩🇪
We study three-flavor octet baryons by using the so-called extended Linear Sigma Model (eLSM). Within a quark-diquark picture, the requirement of a mirror assignment naturally leads to the consideration of four spin- $\frac{1}{2}$ baryon multiplets. A reduction of the Lagrangian to the two-flavor case leaves four doublets of nucleonic states which mix to form the experimentally observed states $N (939)$ , $N (1440)$ , $N (1535)$ and $N (1650)$ . We determine the parameters of the nucleonic part of the Lagrangian from a fit to masses and decay properties of the aforementioned states. By tracing their masses when chiral symmetry is restored, we conclude that the pairs $N (939)$ , $N (1535)$ and $N (1440)$ , $N (1650)$ form chiral partners.
↳ hep-phnucl-thJ.Phys.Conf.Ser.(2016)·0 citations
05
A Lagrangian formulation of relativistic Israel-Stewart hydrodynamics
Giorgio Torrieri🇧🇷 · David Montenegro🇧🇷
We rederive relativistic hydrodynamics as a Lagrangian effective theory using the doubled coordinates technique, allowing us to include dissipative terms. We include Navier-Stokes shear and bulk terms, as well as Israel-Stewart relaxation time terms, within this formalism. We show how the inclusion of shear viscosity, and the requirement of a bounded energy-momentum "vacuum", forces the inclusion of the Israel-Stewart term into the theory, thereby providing a justification for the origin and uniqueness of these terms.
↳ hep-thhep-phnucl-thphysics.flu-dynPRD(2016)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE

The eLSM at nonzero density

Equation of state and transition temperatures in the quark-hadron hybrid model

Three-flavor chiral effective model with four baryonic multiplets within the mirror assignment

A Lagrangian formulation of relativistic Israel-Stewart hydrodynamics

Affiliations