Photon Emission from a Medium-Modified Shower Evolution

TL;DR

This paper introduces a medium-modified shower evolution model to estimate photon emission from jets in heavy-ion collisions, revealing limitations of the leading parton energy loss approximation.

Contribution

It presents a novel approach that incorporates virtuality evolution and subleading parton emissions for more accurate photon yield predictions.

Findings

Leading parton energy loss approximation is insufficient for photon emission.

Medium-modified shower evolution provides a more comprehensive description.

Photon yields are significantly affected by virtuality and subleading emissions.

Abstract

Photons from the interaction of a highly energetic jet with a thermal medium are an important contribution to the total photon yield measured in ultrarelativistic heavy-ion collisions and also an important probe to study the medium degrees of freedom. Previously this contribution has often been computed in the context of a leading parton energy loss approximation. In this work, jet-medium interaction photons are instead estimated using a medium-modified shower evolution model, where the energy degradation due to vacuum radiation prior to medium formation, the virtuality evolution of intermediate states and the photon emission from subleading shower partons is taken into account consistently. The results indicate that the leading parton energy loss approximation does not appear to work well for photon emission from jet-medium interaction.