Do lattice data constrain the vector interaction strength of QCD?

Jan Steinheimer,Stefan Schramm

doi:10.1016/j.physletb.2014.07.018

Jan Steinheimer, Stefan Schramm

Open Access

https://doi.org/10.1016/j.physletb.2014.07.018

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Abstract

We show how repulsive interactions of deconfined quarks as well as confined hadrons have an influence on the baryon number susceptibilities and the curvature of the chiral pseudo-critical line in effective models of QCD. We discuss implications and constraints for the vector interaction strength from comparisons to lattice QCD and comment on earlier constraints, extracted from the curvature of the transition line of QCD and compact star observables. Our results clearly point to a strong vector repulsion in the hadronic phase and near-zero repulsion in the deconfined phase.

Highlights

Quantum Chromo Dynamics (QCD) at extreme conditions of temperature and/or density is a central topic of many experimental and theoretical investigations
The most interesting feature of this figure is the strong dependence of the second-order baryon number susceptibility on the value of the free quark repulsive interaction gVQ
We have shown that lattice results for the baryon number susceptibilities can be used, even to lowest order, to constrain the repulsive vector interaction strength of quarks in the deconfined phase

Summary

Introduction

Quantum Chromo Dynamics (QCD) at extreme conditions of temperature and/or density is a central topic of many experimental and theoretical investigations. The role of the repulsive vector interaction in QCD has become a much discussed topic in recent literature. It is important for the general understanding of the strong interaction and has concrete implications for effective models of QCD regarding the location of the hadron-quark transition [1, 2, 3]. In this work we propose that such an independent determination has been provided by the conserved charge susceptibilities evaluated with lattice QCD at μB = 0 These susceptibilities quantify the fluctuations of the conserved charges of QCD, in particular the net baryon number. The purpose of this paper is to first reproduce the results from [7], though with a different model for the quark phase, and advance

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