We present the first measurement of the mass of the top quark of tt-bar --> ell nu-bar bb-bar qq-bar events (where ell = e, mu) selected by identifying jets containing a muon candidate from the semileptonic decay of heavy-flavor hadrons (soft muon b-tagging). The p anti-p collision data used corresponds to an integrated luminosity of 2 fb-1 and was collected by the CDF II detector at the Fermilab Tevatron. The measurement is based on a novel technique exploiting the invariant mass of a subset of the decay particles, specifically the lepton from the W boson of the t --> Wb decay, and the muon from a semileptonic b decay. We fit template histograms, derived from simulation of tt-bar events and a modeling of the background, to the mass distribution observed in the data and measure a top quark mass of 180.5 +/- 12.0(stat.) +/- 3.6(syst.) GeV/c2, consistent with the current world average.
Measurement of the Top Quark Mass Using the Invariant Mass of Lepton Pairs in Soft Muon b-tagged Events
CASTRO, ANDREA;DENINNO, MARIA MADDALENA;MOGGI, NICCOLO';RIMONDI, FRANCO;ZUCCHELLI, STEFANO
2009
Abstract
We present the first measurement of the mass of the top quark of tt-bar --> ell nu-bar bb-bar qq-bar events (where ell = e, mu) selected by identifying jets containing a muon candidate from the semileptonic decay of heavy-flavor hadrons (soft muon b-tagging). The p anti-p collision data used corresponds to an integrated luminosity of 2 fb-1 and was collected by the CDF II detector at the Fermilab Tevatron. The measurement is based on a novel technique exploiting the invariant mass of a subset of the decay particles, specifically the lepton from the W boson of the t --> Wb decay, and the muon from a semileptonic b decay. We fit template histograms, derived from simulation of tt-bar events and a modeling of the background, to the mass distribution observed in the data and measure a top quark mass of 180.5 +/- 12.0(stat.) +/- 3.6(syst.) GeV/c2, consistent with the current world average.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.