Multipartonic cascades in expanding media

TL;DR

This paper models partonic cascades in expanding media, incorporating quark and gluon dynamics, and compares theoretical predictions with experimental data to understand jet quenching phenomena.

Contribution

It introduces coupled evolution equations with splitting kernels for quark and gluon cascades in various expanding media, providing new insights into medium-modified jet spectra and quenching effects.

Findings

Scaling features of partonic spectra across media types

Impact of medium expansion on jet $R_{AA}$ and $v_2$

Differences in quenching parameters for different media expansions

Abstract

In this work, we introduce both gluon and quark degrees of freedom for describing the partonic cascades inside the medium. We present numerical solutions for the set of coupled evolution equations with splitting kernels calculated for the static, exponential and Bjorken expanding media to arrive at medium-modified parton spectra for quark and gluon initiated jets respectively. We discuss novel scaling features of the partonic spectra between different types of media. Next, we study the inclusive jet $R_{AA}$ by including phenomenologically driven combinations of quark and gluon fractions inside a jet. In addition, we have also studied the effect of the nPDF as well as vacuum like emissions on the jet $R_{AA}$. Differences among the estimated values of quenching parameter for different types of medium expansions are noted. Next, the impact of the expansion of the medium on the rapidity dependence of the jet $R_{AA}$ as well as jet $v_2$ are studied in detail. Finally, we present qualitative results comparing the sensitivity of the time for the onset of the quenching for the Bjorken profile on these observables. All the quantities calculated are compared with the recent ATLAS data.