Quark Matter 2014 - XXIV International Conference on Ultrarelativistic Nucleus-Nucleus Collisions

19-24 May 2014
Europe/Zurich timezone

Renormalization of the jet-quenching parameter

21 May 2014, 13:10
20m

titanium

Contributed Talk New Theoretical Developments

Speaker

yacine mehtar-tani (IPhT CEA/Saclay)

Description

In the context of the recently derived probabilistic picture of in-medium jet evolution, arXiv:1311.5823 [hep-ph], we study radiative corrections which yield potentially large double logarithms, $\alpha_s ln^2 L$, for large enough medium length $L$ (arXiv:1304.7677 [hep-ph]).  We show in particular that, due to a large separation of time scales, these corrections can be reabsorbed in a renormalization of the jet-quenching parameter, $\hat q$, in both the collision rate and radiative rate, preserving the probabilistic picture.  As a major consequence of this analysis, the new renormalized quenching parameter is enhanced compared to the standard perturbative estimate. This yields in particular an increase of radiative energy loss of a fast parton traversing a QCD medium, which scales as $L^{2+\gamma}$ where the anomalous dimension $\gamma=2\sqrt{N_c \alpha_s/\pi}$, as compared to the standard estimate that yields a scaling in $L^2$.
On behalf of collaboration: None

Primary author

yacine mehtar-tani (IPhT CEA/Saclay)

Co-author

Prof. Jean-Paul Blaizot (IPhT CEA/Saclay)

 Slides