Polarized $\phi$ meson rates with viscous corrections at RHIC

TL;DR

This paper investigates how viscous effects influence the polarization and emission rates of $$ mesons in ultra-relativistic heavy ion collisions, highlighting non-isotropic corrections due to shear and bulk viscosities.

Contribution

It introduces viscous corrections to $$ meson emission rates, accounting for non-equilibrium effects in heavy ion collision environments.

Findings

Viscous effects induce non-isotropic corrections to $$ meson emission.

Shear and bulk viscosities impact $$ meson polarization.

Emission remains isotropic at leading order, with anisotropies emerging at next-to-leading order.

Abstract

We discuss the emission of $\phi$ mesons with longitudinal and transverse polarization in ultra-relativistic heavy ion collisions. In the hadronic phase and in leading order in the kaon diluteness, $\phi$ emission is isotropic and driven by the flavor singlet and octet vector spectral functions. At next to leading order, the emissivities receive a non-isotropic correction from the flavor octet spectral function, and the non-equilibrium contributions originating from the shear and bulk viscosities. Implications for the $\phi$ meson alignment in heavy-ion collisions are discussed.