# 10th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions

May 31, 2020 to June 5, 2020
Online
US/Central timezone

## The problem of overlapping formation times: A complete result for QCD

Jun 3, 2020, 12:45 PM
20m
https://cern.zoom.us/j/95672106059

#### https://cern.zoom.us/j/95672106059

Oral Presentation New Theoretical Developments

### Speaker

Dr Shahin Iqbal (Institute of Particle Physics, Central China Normal University)

### Description

The splitting processes of bremsstrahlung and pair-production in a medium are coherent over large distances in the high energy limit leading to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. Avoiding soft-emission approximations and working in the large-Nc limit, we consider corrections to the LPM effect from cases where the coherence lengths of two consecutive splittings overlap. In this work, we present (i) complete results for the case of two overlapping gluon splittings (e.g. $g\rightarrow gg\rightarrow ggg$ and virtual corrections to single splitting $g\rightarrow gg^{*}\rightarrow ggg^{*}\rightarrow gg$) and (ii) confirm that earlier leading-log results for these effects are reproduced by our more-complete results in the appropriate soft limit. We also discuss how to combine the effects of overlapping real double splitting with the corresponding virtual corrections to single splitting in order to calculate IR-safe quantities such as in-medium energy loss.

Track New Theoretical Developments Contributed Talk

### Primary authors

Peter Arnold (University of Virginia) Tyler Gorda (University of Virginia) Dr Shahin Iqbal (Institute of Particle Physics, Central China Normal University)

### Presentation materials

 Recording Shahin_HP2020.pdf