Initial-state splitting kernels in cold nuclear matter

TL;DR

This paper derives advanced medium-induced splitting kernels for energetic partons in dense QCD matter, extending previous models beyond the soft gluon approximation to improve understanding of initial-state energy loss in nuclear collisions.

Contribution

It introduces a new derivation of medium-induced splitting kernels within SCET_G, going beyond the soft gluon approximation, relevant for cold nuclear matter phenomenology.

Findings

Numerical comparison with previous models shows improved accuracy.

Results suggest significant impact on initial-state energy loss calculations.

Enhanced kernels are applicable to p+A and A+A collision analyses.

Abstract

We derive medium-induced splitting kernels for energetic partons that undergo interactions in dense QCD matter before a hard-scattering event at large momentum transfer $Q^2$. Working in the framework of the effective theory ${\rm SCET}_{\rm G}\,$, we compute the splitting kernels beyond the soft gluon approximation. We present numerical studies that compare our new results with previous findings. We expect the full medium-induced splitting kernels to be most relevant for the extension of initial-state cold nuclear matter energy loss phenomenology in both p+A and A+A collisions.