We report a measurement of the top quark mass, m_t, obtained
from p anti-p collisions at s**(1/2) ñ.96 TeV at the Fermilab Tevatron
using the CDF II detector. We analyze a sample corresponding to an
integrated luminosity of 1.9 fb-1. We select events with an electron
or muon, large missing transverse energy, and exactly four high-energy
jets in the central region of the detector, at least one of which is
tagged as coming from a b quark. We calculate a signal likelihood using
a matrix element integration method, where the matrix element is modified
by using effective propagators to take into account assumptions on event
kinematics. Our event likelihood is a function of m_t and a parameter
JES that determines in situ the calibration of the jet energies. We use a
neural network discriminant to distinguish signal from background events.
We also apply a cut on the peak value of each event likelihood curve to
reduce the contribution of background and badly reconstructed events.
Using the 318 events that pass all selection criteria, we find m_t ñ72.7
+/- 1.8 (stat. + JES) +/- 1.2 (syst.) GeV/c2.
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Updated: Thursday, 2009 April 16 09:34:00 CDT automatically from input from carol picciolo