Measurement of the Top Quark Mass using Quantities with Minimal Dependence on the Jet Energy Scale |
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Ford Garberson, Joe Incandela, Sue Ann Koay, Roberto Rossin
UCSB Christopher Hill University of Bristol |
Top Mass Results with 1.9 fb-1 of Data: |
175.3 ± 6.2 (stat) ± 3.0 (syst) GeV/c2, for the combined measurement |
176.7+10.0-8.9 (stat) ± 3.4 (syst) GeV/c2, for the decay length measurement alone |
173.5+8.9-9.1 (stat) ± 4.2 (syst) GeV/c2, for the lepton transverse momentum measurement alone |
The total missing transverse energy (MET) in the event is required to be greater than 20 GeV, and a minimum of three jets must also be identified with reconstructed transverse energies greater than 20 GeV. b-jets are identified (tagged) using the SecVtx algorithm. In order for the event to pass selection, at least one jet must be tagged as a b for events with four or more jets of ET greater than 20 GeV, and at least two jets must be tagged as a b for events with exactly three jets of ET greater than 20 GeV.
Signal, background, and data for the L2d distribution, using hypothesis top mass M=178 GeV/c2 | Signal, background, and data for the LepPt distribution, using hypothesis top mass M=173 GeV/c2 |
Expected central values and one sigma confidence intervals of L2d mean results depending on top mass. Solid lines show the plus and minus one sigma statistical uncertainties from data. | Expected central values and one sigma confidence intervals of LepPt mean results depending on top mass. Solid lines show the plus and minus one sigma statistical uncertainties from data. |
Likelihood fit results for data. |
Offset between input and output top masses (residuals) expected for L2d, LepPt, and in combination. Statistical errors are based on number of pseudoexperiments thrown and finite Monte Carlo statistics. |
Pull widths expected for L2d, LepPt, and in combination. Statistical errors are based on number of pseudoexperiments thrown and finite Monte Carlo statistics. Statistical errors are based on number of pseudoexperiments thrown and finite Monte Carlo statistics. For the L2d and LepPt measurements, for a given pseudoexperiment the "+" uncertainty is used if the measured result is above the expected value, and the "-" uncertainty is used if the measured result is below the expected value. |
Observed statistical error and expectations for a top mass of 175 GeV/c2 |
Background predictions compared with data in the one jet control region for L2d and LepPt | |
Background predictions compared with data in the two jet control region for L2d and LepPt |
Jet Energy Scale Mass Uncertainties |
Final Systematic Results |