English Intern
  • Seminar Elementarteilchenphysik
Theoretische Physik II

Assistant Prof. Dr. Marek Schönherr

Durham University

T a l k : 22. June 2023

The role of colour-coherence in NLL accurate parton evolution


Parton showers form an integral part of any Monte-Carlo event generator. They evolve the primary hard parton ensemble that is produced in the initial hard collision down to scales at the boundary to the non-perturbative transition into observable hadrons using a fully differential form of the Sudakov equations, and thus are essential in providing theoretical predictions for many observables at hadron and lepton colliders. With the advent of precision data taking at the LHC and proposed future colliders, the theoretical accuracy of our prediction must keep pace to allow for a meaningful interpretation of said data. Hence, the theoretical accuracy of parton showers has come under scrutiny and several short-comings have been identified in existing algorithms. In this talk, I will present a recent formulation, the Alaric (a logarithmically accurate resummation in C++) parton shower, and demonstrate its NLL accuracy and colour coherence, essential for a full analytical control of its resummation properties, as well as its ability to describe existing precision measurements.