# Rencontre de Physique des Particules 2015

15-16 January 2015
Institut Henri Poincaré
Europe/Paris timezone

## Universality of perturbative QCD soft radiation in ee, ep, and pp collisions

15 Jan 2015, 09:53
14m
Chair: Sébastien Descotes-Genon, Amphi Hermite (Institut Henri Poincaré)

### Chair: Sébastien Descotes-Genon, Amphi Hermite

#### Institut Henri Poincaré

11, rue Pierre et Marie Curie 75005 Paris

### Speaker

Ou Zhang (University of Arizona and IPN-Orsay)

### Description

Soft radiation consists of coherent low energy gluons that interact with initial and final state jets at wide angles from the jet axis, and we show that this soft radiation in ee, ep and pp collisions is universal to order $\alpha_s^2$ in perturbation theory. We factor this soft radiation out of the multi-scale cross-section using Soft Collinear Effective Theory, which is an effective field theory of QCD for processes with high energy, light-like degrees of freedom interacting via soft degrees. The universality of soft radiation suggests that low energy QCD radiation is independent of the process and can be decoupled from the high-energy, short-distance jet structure.

### Presentation Materials

 Transparents