Non-linear evolution in QCD at low-x beyond leading order

Apr 9, 2019, 9:30 AM
20m
Cavallerizza Reale - Aula Multifunzione

Cavallerizza Reale - Aula Multifunzione

Via Verdi, 9 Turin
Parallel Session Talk WG2: Low-x and Diffraction WG2: Small-x and Diffraction

Speaker

Dr Dionysios Triantafyllopoulos (ECT*/FBK)

Description

The NLO Balitsky-Kovchegov (BK) equation describing the high-energy evolution of the scattering between a dilute projectile and a dense target suffers from instabilities unless it is supplemented by a proper resummation of large (anti-)collinear logarithms. Earlier studies showed that if one expresses the evolution in terms of the rapidity of the dilute projectile, the dominant anti-collinear contributions can be resummed to all orders. However, in phenomenological applications, the results must be re-expressed in terms of the rapidity of the dense target. We show that although they lead to stable evolution equations, resummations expressed in the rapidity of the dilute projectile show a strong, unwanted, scheme dependence when their results are translated in terms of the target rapidity. Here, we work directly in the rapidity of the dense target where anti-collinear contributions are absent but where new, collinear, instabilities arise. These are milder since disfavoured by the typical BK evolution. Studying several prescriptions for resumming these new double logarithms, we find only little scheme dependence. The resummed equations are non-local in rapidity and can be extended to full NLO accuracy.

Primary author

Co-authors

Bertrand Ducloue (IPhT Saclay) Edmond Iancu (Université Paris-Saclay (FR)) Alfred Mueller (Columbia University) Gregory Soyez (IPhT, CEA Saclay)

Presentation materials