Free Meson Seminars

Nonperturbative corrections to the groomed jet mass

by Mr. Aditya Pathak (University of Vienna)

Friday, January 4, 2019 from to (Asia/Kolkata)
at A304
Description With the advent of resummation and factorization techniques in QCD in the 80s and 90s we developed powerful tools to calculate event shape distributions with ever increasing accuracy, such as thrust or jet mass. This has paved the way for precise measurement of parameters such as top mass or the strong coupling, αs. While a successful program at LEP, the more complex collider environment of the LHC has called for exploring techniques that can help reduce the contamination of an event shape measurement from sources such as the underlying event or pile-up. One category of such a technique that has been amenable to theoretical calculations is the "Jet grooming".

Jet grooming involves selecting certain particles in a given event, throwing away others, and calculating the event shape variable on the selected set of particles. This is done in a way such that what gets thrown away resembles the “contamination”, and the key information, accessible to perturbative QCD calculations, is preserved by the kept-particles. The result is a reduced correction to the perturbative cross section from hadronization and the underlying event. However, despite these advantages, due to complicated nature of the algorithm, it is a non trivial problem to include consistently a description of the remaining nonperturbative effects. This has so far been done exclusively by making use of Monte Carlo Event Generators and an analytical understanding is lacking. In this talk I address these issues, deriving results solely from field theory wherever possible.