Chiral transition in a strong magnetic background

TL;DR

This paper investigates how strong magnetic fields influence the chiral phase transition in QCD, showing that magnetic fields can turn a crossover into a weak first-order transition, with implications for heavy ion collisions and early universe conditions.

Contribution

It provides a detailed calculation of the effective potential in the linear sigma model with quarks under strong magnetic fields, revealing a change in the transition's nature.

Findings

Magnetic fields of eB ~ 5 m_π^2 turn crossover into weak first-order transition.

The study discusses implications for heavy ion collisions at RHIC and LHC.

Potential effects on the primordial QCD transition are considered.

Abstract

The presence of a strong magnetic background can modify the nature and the dynamics of the chiral phase transition at finite temperature. We compute the modified effective potential in the linear sigma model with quarks to one loop in the $\bar{MS}$ scheme for $N_{f}=2$. For fields $eB\sim 5 m_{\pi}^{2}$ and larger a crossover is turned into a weak first-order transition. We discuss possible implications for non-central heavy ion collisions at RHIC and LHC, and for the primordial QCD transition.