Gluon to $q\bar q$ antenna in anisotropic QCD matter: spin-polarized and azimuthal jet observables

TL;DR

This paper investigates how anisotropic QCD media influence the production and spin polarization of quark-antiquark pairs within jets, revealing that medium anisotropy affects azimuthal distributions and spin observables, which can be experimentally probed.

Contribution

It introduces a novel analysis of spin-dependent jet observables in anisotropic QCD matter, linking medium anisotropy to helicity and azimuthal distributions within jets.

Findings

Particle distributions are sensitive to medium anisotropy.

Spin effects couple to azimuthal harmonic components.

Medium anisotropies can be probed via jet spin and azimuthal observables.

Abstract

We study the production of a quark-antiquark antenna in the presence of a dense and anisotropic QCD medium. We assume the antenna to originate from an unpolarized gluon state, and consider both massless and massive final states. The medium anisotropy is captured by allowing the jet quenching coefficient to take different magnitudes in orthogonal directions with respect to the jet axis. We find that the final particle distribution is sensitive to the medium anisotropy, and more importantly, that this effect couples directly to the helicity/spin of the final states. We propose to look into these effects by performing a Fourier decomposition of the particle distribution inside the jet. In our medium model, we find that the spin independent terms contribute to the even harmonics of the cosine series. The helicity/spin dependence enters only through the sine Fourier series. We further explore the spin dependence by examining the degree of polarization of the final states in different directions. Our results indicate that the anisotropies present in the QCD matter produced in heavy ion collisions can be probed by studying azimuthal and spin observables inside jets.