The thermal QCD transition with two flavours of twisted mass fermions

TL;DR

This study explores the nature of the thermal QCD transition using twisted mass fermions across various pion masses, analyzing critical temperatures and their scaling behavior to understand the chiral limit.

Contribution

It provides new insights into the scaling behavior of the QCD transition with twisted mass fermions and compares the results with O(4) and first order scenarios.

Findings

Pseudo-critical temperatures are consistent with O(4) scaling for the pion masses studied.

A clear distinction between O(4) and first order scenarios requires lighter pions.

Results suggest current simulations with heavier pions cannot definitively determine the transition's universality class.

Abstract

We investigate the thermal QCD transition with two flavors of maximally twisted mass fermions for a set of pion masses, 300 MeV \textless $m_\pi$ \textless 500 MeV, and lattice spacings $a$ \textless 0.09 fm. We determine the pseudo-critical temperatures and discuss their extrapolation to the chiral limit using scaling forms for different universality classes, as well as the scaling form for the magnetic equation of state. For all pion masses considered we find resonable consistency with O(4) scaling plus leading corrections. However, a true distinction between the O(4) scenario and a first order scenario in the chiral limit requires lighter pions than are currently in use in simulations of Wilson fermions.