Isospin Effect on Baryon and Charge Fluctuations from the pNJL Model

He Liu,Jun Xu

doi:10.3390/universe7010006

Abstract

We have studied the possible isospin corrections on the skewness and kurtosis of net-baryon and net-charge fluctuations in the isospin asymmetric matter formed in relativistic heavy-ion collisions at RHIC-BES energies, based on a 3-flavor Polyakov-looped Nambu–Jona–Lasinio model. With typical scalar–isovector and vector–isovector couplings leading to the splitting of u and d quark chiral phase transition boundaries and critical points, we have observed considerable isospin effects on the susceptibilities, especially those of net-charge fluctuations. Reliable experimental measurements at even lower collision energies are encouraged to confirm the observed isospin effects.

Highlights

Studying the hadron-quark phase transition and exploring the phase structure of quantum chromodynamics (QCD) matter are the fundamental goals of relativistic heavyion collision experiments
Heavy-ion collisions with neutron-rich beams produce isospin asymmetric quark matter consisting of different net numbers of u and d quarks, and the isospin degree of freedom is expected to be increasingly important at lower collision energies with larger μX represents the baryon (μB), related to the QCD phase structure at finite isospin chemical potentials μI [10]
We investigate the isospin effects on the net-baryon and netcharge fluctuations based on the 3-flavor Polyakov-looped NJL model with isovector couplings in both the scalar and vector channels [34], i.e., the scalar–isovector and vector– isovector couplings

Summary

Introduction

Studying the hadron-quark phase transition and exploring the phase structure of quantum chromodynamics (QCD) matter are the fundamental goals of relativistic heavyion collision experiments. The above findings have stimulated experimental measurements of non-Gaussian net-baryon, net-charge, and net-strangeness fluctuations, c√haracterized by the kurtosis and the skewness of their event-by-event distributions, from sNN = 7.7 to 200 GeV at RHIC [16,17,18,19,20,21,22,23], and theoretical studies based on lattice QCD calculations [24,25] as well. For reviews on this topic, we refer the reader to references [26,27]. It is expected that such isospin splittings may affect the susceptibilities of conserved quantities mentioned above

PNJL Model with Isovector Couplings

Isospin Properties of Higher-Order Susceptibilities

Summary and Outlook