From evah@fnal.gov Fri Apr 15 12:05:30 2005 Date: Thu, 14 Apr 2005 16:31:19 -0500 (CDT) From: Eva Halkiadakis To: Evelyn Thomson Subject: Re: fix public mtop summary plot How's this? Top Mass Measurements at CDF in Run II ====================================== CDF has been exploring several different techniques for the top mass measurement. The best single number is from a mass template technique in the lepton+jets channel (ttbar-> lvbqqb). The observed invariant mass of the hadronic W boson decay is used to reduce the largest systematic uncertainty arising from the jet energy scale. The top quark mass and hadronic W boson mass distributions reconstructed in data are compared to Monte Carlo expectations to determine simultaneously the top quark mass and the jet energy scale. CDF Run II preliminary 173.5 +2.7/-2.6 (stat) +/- 2.5 (jet energy) +/- 1.5 (syst) GeV/c2 This is using 318 pb-1 of Run II data (March 2002-September 2004). The systematic is dominated by the modeling of the calorimeter response (new forward calorimeter, extra material in new tracking system). This constitutes the best measurement of the top quark mass to date. For comparison, the best single result from the lepton+jets channel, with about 110 pb-1 of Run I data (1994-1995), is CDF Run I result 176.1 +- 5.1 (stat) +- 5.3 (syst) GeV/c2 D0 Run I result 180.1 +- 3.6 (stat) +- 3.9 (syst) GeV/c2 World average 178.0 +- 4.3 GeV/c2 (hep-ex/0404010) (Run I only) -------------------------------------- Eva Halkiadakis University of Rochester CDF 168E, MS 318 email: evah@fnal.gov office phone: (630)840-8406 fax: (630)840-2968 cell phone: (630)452-4489 http://b0urpc.fnal.gov/~evah/ --------------------------------------