Top Quark Mass in Dilepton Channel Using Matrix Element

Summer 2007: 1.8 fb-1

B. Jayatilaka1, D. Whiteson2, M. Tecchio3, A. Kotwal1

1 Duke University
2 University of California, Irvine
3 University of Michigan

CDF Collaboration

E-mail authors

We present a measurement of the top quark mass in the dilepton channel using a technique in which we form a posterior probability for the mass as a product of the per-event differential cross-section for leading order top quark pair production. The calculation of the differential cross section for processes which produce background events are used to reduce the impact of background events in the sample.

In 1.8 fb-1 of Run II data, we expect a statistical uncertainty of 3.2 GeV/c2 if Mtop=175.0 GeV/c2. We measure

Mtop = 170.4 ± 3.1 (stat.) ± 3.0 (syst.) GeV/c2

Documentation

Tables and Plots

Description jpg pdf/eps
Final posterior probability density as a function of top pole mass for the 125 dilepton candidate events in data. pdf/eps
Expected distribution of errors from MC (Mt=165 GeV/c2) and measured error in data. 26% of pseudo-experiments had an error lower than that measured in data. pdf/eps
Response for pseudo-experiments of signal and background events. pdf/eps
Residual, pull mean, and pull width for varying top mass MC samples after scaling of statistical error. The error scaling factor is S=1.11 pdf
Table of systematic uncertainties. pdf
Evaluation of the ttbar probability (evaluated at Mtop=170 GeV/c2) for simulated events, scaled by expected contribution to the sample composition, and for observed events. pdf/eps
Evaluation of the Z+2 jet probability for simulated events, scaled by expected contribution to the sample composition, and for observed events. pdf/eps
Evaluation of the WW+2 jet probability for simulated events, scaled by expected contribution to the sample composition, and for observed events. pdf/eps
Evaluation of the W+3 jet probability for simulated events, scaled by expected contribution to the sample composition, and for observed events. pdf/eps
Bo Jayatilaka
Last modified: 8/09/07