Direct measurement of the mass difference between top and antitop quarks

Authors

V. M. Abazov, Joint Institute for Nuclear Research, Dubna, Russia
Kenneth A. Bloom, University of Nebraska-LincolnFollow
Daniel Claes, University of Nebraska-LincolnFollow
Kayle DeVaughan, University of Nebraska-Lincoln
Aaron Dominguez, University of Nebraska-LincolnFollow
Michael Eads, University of Nebraska-LincolnFollow
D. Johnston, University of Nebraska-LincolnFollow
Ioannis Katsanos, University of Nebraska-LincolnFollow
Sudhir Malik, University of Nebraska-LincolnFollow
Gregory Snow, University of Nebraska-LincolnFollow
D0 Collaboration

Date of this Version

2011

Citation

PHYSICAL REVIEW D 84, 052005 (2011)

Comments

Copyright 2011 American Physical Society; DOI: 10.1103/PhysRevD.84.052005

Abstract

We present a direct measurement of the mass difference between top and antitop quarks (∆m) in lepton + jets tt final states using the ‘‘matrix element’’ method. The purity of the lepton + jets sample is enhanced for tt events by identifying at least one of the jets as originating from a b quark. The analyzed data correspond to 3.6 fb-1 of pp collisions at √s = 1.96 TeV acquired by D0 in Run II of the Fermilab Tevatron Collider. The combination of the e + jets and µ + jets channels yields ∆m =0.8 ± 1,8 stat ± 0.5(syst) GeV, which is in agreement with the standard model expectation of no mass difference.