Monte Carlo Top Quark Mass Calibration

Bahman Dehnadi, André H. Hoang, Vicent Mateu, Moritz Preißer (Corresponding author), Ian Stewart

Publications: Contribution to journalMeeting abstract/Conference paperPeer Reviewed


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 relevant for kinematic reconstruction, relating mMCt to field theory masses is a non-trivial task. In this talk we report on 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 a close relation to the invariant mass of the particles coming from the top decay. The theoretical ingredients of the QCD prediction are reviewed. Fitting e+e− 2-Jettiness calculations at NLL/NNLL order to \Pythia~8.205, we find that mMCt agrees with the MSR mass mMSRt,1GeV within uncertainties. At NNLL we find mMCt=mMSRt,1GeV+(0.18±0.22)GeV. mMCt can differ from the pole mass mpolet by up to 600MeV, and using the pole mass generally leads to larger uncertainties. At NNLL we find mMCt=mpolet+(0.57±0.28)GeV as the fit result. In contrast, converting mMSRt,1GeV obtained at NNLL to the pole mass gives a result for mpolet that is substantially larger and incompatible with the fit result. We also explain some theoretical aspects relevant for employing the C-parameter as an alternative calibration observable.
Original languageEnglish
Article number062
Number of pages10
JournalProceedings of Science (PoS)
Publication statusPublished - 2 Jul 2018
Event13th International Symposium on Radiative Corrections (Applications of Quantum Field Theory to Phenomenology): RADCOR2017 - Hotel Hollweger, St. Gilgen, Austria
Duration: 25 Sep 201729 Sep 2017

Austrian Fields of Science 2012

  • 103024 Quantum field theory


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