Top quark mass calibration for Monte-Carlo event generators

The most precise top quark mass measurements use kinematic reconstruction methods, determining the top mass parameter of a Monte Carlo event generator, mMCt. Due to the complicated interplay of hadronization and parton shower dynamics in Monte Carlo event generators, relating mMCt to field theory ma...

Full description

Bibliographic Details
Main Authors: Hoang, Andre, Butenschoen, Mathias, Dehnadi, Bahmand, Mateu, Vicent, Preisser, Moritz, Stewart, Iain W
Other Authors: Massachusetts Institute of Technology. Center for Theoretical Physics
Format: Article
Language:English
Published: Sissa Medialab 2021
Online Access:https://hdl.handle.net/1721.1/137646.2
Description
Summary:The most precise top quark mass measurements use kinematic reconstruction methods, determining the top mass parameter of a Monte Carlo event generator, mMCt. Due to the complicated interplay of hadronization and parton shower dynamics in Monte Carlo event generators, relating mMCt to field theory masses is a non-trivial task. In this talk we present a calibration procedure to determine this relation using hadron level QCD predictions for 2-Jettiness in e+e- annihilation, an observable which has kinematic top mass sensitivity and has a close relation to the invariant mass of the particles coming from the top decay. The theoretical ingredients of the QCD prediction are explained. Fitting e+e- 2-Jettiness calculations at NLL/NNLL order to PYTHIA 8.205, we find that mMCt agrees with the MSR mass at the scale 1 GeV within uncertainties, mMCt mMSRt;1GeV, but differs from the pole mass by 900/600MeV.