# Scale Separation and Effective Field Theory for Light Particles in High Energy Interactions

Date and time |
Jan 12, 2018 from 02:00 PM to 03:00 PM |
---|---|

Location | MP 134 |

## Ray Goerke

**
Department of Physics, University of Toronto
**

Scale separation is a common phenomena in which physics at large
distances does not depend strongly on physics at shorter distances;
making it possible, for example, for us to have learned a great deal
about the dynamics of the solar system before the development of quantum
mechanics. In high energy physics, scale separation is exemplified when
short distance processes mediated by heavy particles or large momentum
transfers can be factorized and decoupled from the long distance
processes they contribute to. This phenomena can be used to separate
perturbative, calculable physics from non-perturbative, incalculable
physics, and it can also be used to improve the precision of theoretical
predictions for the Standard Model when combined with resummation.

A powerful framework for taking advantage of scale separation in
theoretical high energy physics is effective field theory. In this talk
I discuss the application of effective field theory to factorization and
resummation in high energy processes involving light QCD degrees of
freedom (quarks and gluons) that typically produce jets or jet-like
final states. Specifically, I discuss Soft Collinear Effective Theory
(SCET) as the effective theory used to sum Sudakov logarithms, which
limit theoretical precision in such processes. I report on a new
formalism we have developed for SCET that we believe leads to a better
theoretical understanding of the physics involved and streamlines the
computation of subleading corrections to effective theory calculations.