Spontaneous CP violating quark scattering from asymmetric $Z\left(3\right)$ interfaces in QGP

TL;DR

This paper investigates how asymmetric Z(3) domain walls in quark-gluon plasma influence spontaneous CP violation during quark scattering, revealing that asymmetries affect quark effective mass and could impact cosmological and heavy-ion collision phenomena.

Contribution

It extends previous studies by analyzing the effects of asymmetric Polyakov loop profiles on quark scattering and CP violation in Z(3) domain walls within QGP.

Findings

Asymmetric Polyakov loop profiles alter quark effective mass.

Quark-antiquark scattering asymmetry arises from mass effects, not gauge field reflection.

Potential implications for baryon fluctuations in cosmology and heavy-ion collisions.

Abstract

In this paper, we extend our earlier study of spontaneous CP violating scattering of quarks and anti-quarks from QCD $Z\left(3\right)$ domain walls for the situation when these walls have asymmetric profiles of the Polyakov loop order parameter $l(x)$. Dynamical quarks lead to explicit breaking of $Z(3)$ symmetry, which lifts the degeneracy of the $Z(3)$ vacua arising from spontaneous breaking of the $Z(3)$ symmetry in the quark-gluon plasma (QGP) phase. Resulting domain walls have asymmetric profile of $l(x)$ (under reflection $x \rightarrow -x$ for a domain wall centered at the origin). We calculate the background gauge field profile $A_0$ associated with this domain wall profile. Interestingly, even with the asymmetric $l(x)$ profile, quark-antiquark scattering from the corresponding gauge field configuration does not reflect this asymmetry. We show that the expected asymmetry in scattering arises when we include the effect of asymmetric profile of $l(x)$ on the effective mass of quarks and antiquarks and calculate resultant scattering. We discuss the effects of such asymmetric Z(3) walls in generating quark and antiquark density fluctuations in cosmology, and in relativistic heavy-ion collisions e.g. event-by-event baryon fluctuations.