Monte Carlo Top Quark Mass Calibration

Autor(en)

Bahman Dehnadi, André H. Hoang, Vicent Mateu, Moritz Preißer, Ian Stewart

Abstrakt

The most precise top quark mass measurements use kinematic reconstruction methods, determining the top mass parameter of a Monte Carlo event generator, m^MCt. Due to the complicated interplay of hadronization and parton shower dynamics in Monte Carlo event generators relevant for kinematic reconstruction, relating m^MCt 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 m^MCt agrees with the MSR mass m^MSRt,1GeV within uncertainties. At NNLL we find m^MCt=m^MSRt,1GeV+(0.18±0.22)GeV. m^MCt 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 m^MCt=m^polet+(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 m^polet 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.

Organisation(en)

Teilchenphysik

Externe Organisation(en)

Universität Siegen, Erwin Schrödinger Institut, Universidad de Salamanca, Spanish National Research Council (CSIC), Massachusetts Institute of Technology

Journal

Proceedings of Science (PoS)

Band

290

Anzahl der Seiten

10

Publikationsdatum

07-2018

Peer-reviewed

Ja

ÖFOS 2012

103024 Quantenfeldtheorie

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/monte-carlo-top-quark-mass-calibration(7ec53568-8bc8-41af-8515-5e01bbb769d8).html