Photon Emission from a Medium-Modified Shower Evolution

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.