Screening correlators with chiral Fermions

TL;DR

This study investigates quark-antiquark screening correlators at high temperature using overlap fermions in lattice QCD, revealing stability across lattice spacings and insights into screening lengths and positivity properties.

Contribution

It provides the first detailed analysis of screening correlators with chiral overlap fermions at high temperature, demonstrating minimal lattice spacing dependence and exploring their physical implications.

Findings

Correlators are stable across different lattice spacings.

Screening correlators follow exponential decay at large distances.

Vector correlator matches ideal gas predictions, scalar deviates at large distances.

Abstract

We study screening correlators of quark-antiquark composites at T=2T_c, where T_c is the QCD phase transition temperature, using overlap quarks in the quenched approximation of lattice QCD. As the lattice spacing is changed from 1/4T to a=1/6T and 1/8T, we find that screening correlators change little, in contrast with the situation for other types of lattice fermions. All correlators are close to the ideal gas prediction at small separations. The long distance falloff is clearly exponential, showing that a parametrization by a single screening length is possible at distances z > 1/T. The correlator corresponding to the thermal vector is close to the ideal gas value at all distances, whereas that for the thermal scalar deviates at large distances. This is examined through the screening lengths and momentum space correlators. There is strong evidence that the screening transfer matrix does not have reflection positivity.