Measurement of the top quark mass with the dynamical likelihood method using lepton plus jets events with b-tags in pp̅ collisions at √s = 1:96 TeV

Authors

A. Abulencia, University of Illinois, Urbana
Kenneth A. Bloom, University of Nebraska-LincolnFollow
CDF Collaboration

Document Type

Article

Date of this Version

5-8-2006

Comments

Published by American Physical Society. Phys. Rev. D 73, 092002 (2006). http://prd.aps.org. Copyright © 2006 American Physical Society. Permission to use.

Abstract

This paper describes a measurement of the top quark mass, M_top, with the dynamical likelihood method (DLM) using the CDF II detector at the Fermilab Tevatron. The Tevatron produces top/antitop (tt̅) pairs in pp̅ collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this analysis was accumulated from March 2002 through August 2004, which corresponds to an integrated luminosity of 318 pb^-1. We use the tt̅ candidates in the ‘‘lepton + jets’’ decay channel, requiring at least one jet identified as a b quark by finding a displaced secondary vertex. The DLM defines a likelihood for each event based on the differential cross section as a function of M_top per unit phase space volume of the final partons, multiplied by the transfer functions from jet to parton energies. The method takes into account all possible jet combinations in an event, and the likelihood is multiplied event by event to derive the top quark mass by the maximum likelihood method. Using 63 tt̅ candidates observed in the data, with 9.2 events expected from background, we measure the top quark mass to be 173.2 _-2.4^+2.6(stat.) ± 3:2(syst.) GeV/c², or 173.2 _-4.0^+4.1 GeV/c².