Top quark mass measurement using the template method in the lepton + jets channel at CDF II

Authors

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

Date of this Version

2-14-2006

Comments

Published by American Physical Society. Phys. Rev. D 73, 032003 (2006). http://prd.aps.org. Copyright © 2006 American Physical Society. Permission to use.

Abstract

This article presents a measurement of the top quark mass using the CDF II detector at Fermilab. Colliding beams of protons and antiprotons at Fermilab’s Tevatron (√s = 1.96 TeV) produce top/antitop pairs, which decay to W⁺W^-bb̅; events are selected where one W decays to hadrons and the other W decays to either ℯ or μ plus a neutrino. The data sample corresponds to an integrated luminosity of approximately 318 pb^-1. A total of 165 tt̅ events are separated into four sub-samples based on jet transverse energy thresholds and the number of b jets identified by reconstructing a displaced vertex. In each event, the reconstructed top quark invariant mass is determined by minimizing a χ² for the overconstrained kinematic system. At the same time, the mass of the hadronically decaying W boson is measured in the same event sample. The observed W boson mass provides an in situ improvement in the determination of the hadronic jet energy scale. A simultaneous likelihood fit of the reconstructed top quark masses and the W boson invariant masses in the data sample to distributions from simulated signal and background events gives a top quark mass of 173.5_-3.8^+3.9 GeV=c².