Measurement of the top quark mass at CDF using the "neutrino $\varphi$ weighting" template method on a lepton plus isolated track sample

Abstract

We present a measurement of the top quark mass with t-tbar dilepton events produced in p-pbar collisions at the Fermilab Tevatron $\sqrt{s}$=1.96 TeV and collected by the CDF II detector. A sample of 328 events with a charged electron or muon and an isolated track, corresponding to an integrated luminosity of 2.9 fb${}^{-1}$, are selected as t-tbar candidates. To account for the unconstrained event kinematics, we scan over the phase space of the azimuthal angles (${\varphi }_{{\nu }_1},{\varphi }_{{\nu }_2}$) of neutrinos and reconstruct the top quark mass for each ${\varphi }_{{\nu }_1},{\varphi }_{{\nu }_2}$ pair by minimizing a ${\chi }^2$ function in the t-tbar dilepton hypothesis. We assign ${\chi }^2$-dependent weights to the solutions in order to build a preferred mass for each event. Preferred mass distributions (templates) are built from simulated t-tbar and background events, and parameterized in order to provide continuous probability density functions. A likelihood fit to the mass distribution in data as a weighted sum of signal and background probability density functions gives a top quark mass of $165.5_{-3.3}^{+3.4}$(stat.)$\pm 3.1$(syst.) GeV/$c^2$.

Submitted to Phys. Rev. D