Logarithmic accuracy of parton showers

by Pier Francesco Monni (CERN)

Thursday 21 Mar 2019, 14:00 → 15:00 Europe/Zurich

Edificio U2, Aula 5017 (Dipartimento di Fisica G. Occhialini, U2, Università degli Studi di Milano-Bicocca)

I present some first fundamental elements of an approach for assessing the logarithmic accuracy of parton-shower algorithms based on two broad criteria: their ability to reproduce the singularity structure of multi-parton matrix elements, and their ability to reproduce logarithmic resummation results. As a case study, I consider properties of two transverse momentum ordered final-state showers, examining features up to second order in the strong coupling. In particular, it is possible to identify regions where they fail to reproduce the known singular limits of matrix elements. This inevitably affects the logarithmic resummation accuracies of the shower, both in terms of leading (double) logarithms at subleading N_C and next-to-leading (single) logarithms at leading N_C. This work lays the theoretical foundation for the development of a higher order parton shower algorithm.

Milano_PS.pdf