Simple implementation of color coherence for the resumation of soft BDMPS-Z gluons

TL;DR

This paper introduces a straightforward method to incorporate color coherence effects into the in-medium evolution equations of QCD jets, improving the understanding of gluon emissions in dense media.

Contribution

It presents a simple implementation of color (de)coherence effects into the Markovian in-medium jet evolution equations, aligning with previous findings on in-medium color coherence.

Findings

The new evolution equation respects color coherence between emitters.

The implementation aligns with prior studies on in-medium color coherence.

The approach simplifies the inclusion of coherence effects in jet evolution models.

Abstract

The evolution of QCD jets under the influence of a dense colored medium leads to the non trivial modification of the gluon emission spectrum. In the multiple soft scattering regime, for sufficiently large media, soft and wide angle emissions can be resummed (in the planar limit of QCD) due to the small formation time of each gluon emission. Similarly to DGLAP evolution, such cascades correspond to pure Markovian processes and interferences between partons are neglected. In this strict limit, color coherence effects are absent. In the vacuum this coherence effect is critical to guarantee that the shower is angular ordered. In the medium, it is known that such color coherence effects might play a role in suppressing radiation at intermediate emission angles. We present a simple procedure to implement color (de)coherence effects into the in-medium evolution equations obtained in the pure Markovian approximation. We verify that the result obtained is in accordance with previous studies regarding the role of in-medium color coherence in the evolution of the QCD antenna. The new evolution equation incorporates a novel emission kernel which enforces color coherence between emitters.