# Quark Matter 2017

Feb 5 – 11, 2017
Hyatt Regency Chicago
America/Chicago timezone

## O(g) NLO effects in transport coefficients

Feb 7, 2017, 2:00 PM
20m
Regency A

### Regency A

Oral QCD at High Temperature

### Speaker

Jacopo Ghiglieri (CERN (CH))

### Description

Transport coefficients of QCD like the shear viscosity $\eta$ and the diffusion of baryon number $D$ have been determined at leading order in perturbation theory by Arnold, Moore and Yaffe (AMY). I will show how these transport coefficients are sensitive to $O(g)$ corrections arising from interactions with soft gluons. These NLO effects enter as corrections to the transverse momentum broadening coefficient $\hat {q}$, to longitudinal momentum broadening, to quark-gluon conversions, to collinear 1<->2 processes and to wider-angle bremsstrahlung (semi-collinear processes). These corrections have been computed using a Euclidean formalism pioneered by S. Caron-Huot, which exploits the analytical properties of amplitudes supported on light fronts. There remain only two coefficients whose $O(g)$ corrections are unknown, as I will show.

I will show the effect of all known corrections to the value of the transport coefficients. In particular, the large $O(g)$ contribution to $\hat{q}$ is the leading NLO effect and it reduces the value of the transport coefficients very significantly. I will also estimate the effect of the unknown coefficients.

Preferred Track QCD at High Temperature Not applicable

### Primary author

Jacopo Ghiglieri (CERN (CH))