A measurement of the W boson helicity is presented, where the W boson originates from the decay of a top quark produced in pp collisions. The event selection, optimized for reconstructing a single top quark in the final state, requires exactly one isolated lepton (muon or electron) and exactly two jets, one of which is likely to originate from the hadronization of a bottom quark. The analysis is performed using data recorded at a center-of-mass energy of 8 TeV with the CMS detector at the CERN LHC in 2012. The data sample corresponds to an integrated luminosity of 19.7 fb−1. The measured helicity fractions are FL = 0.298 ± 0.028 (stat) ± 0.032(syst), F0 = 0.720 ± 0.039 (stat) ± 0.037(syst), and FR = −0.018 ± 0.019 (stat) ± 0.011(syst). These results are used to set limits on the real part of the tWb anomalous couplings, gL and gR.

Measurement of the W boson helicity in events with a single reconstructed top quark in p p collisions at root s=8 TeV

ALBERGO, Sebastiano Francesco;CAPPELLO, GIGI;CHIORBOLI, MASSIMILIANO;COSTA, Salvatore;GIORDANO, FERDINANDO;POTENZA, Renato Carlo;TRICOMI, Alessia Rita;TUVE', Cristina Natalina;
2015

Abstract

A measurement of the W boson helicity is presented, where the W boson originates from the decay of a top quark produced in pp collisions. The event selection, optimized for reconstructing a single top quark in the final state, requires exactly one isolated lepton (muon or electron) and exactly two jets, one of which is likely to originate from the hadronization of a bottom quark. The analysis is performed using data recorded at a center-of-mass energy of 8 TeV with the CMS detector at the CERN LHC in 2012. The data sample corresponds to an integrated luminosity of 19.7 fb−1. The measured helicity fractions are FL = 0.298 ± 0.028 (stat) ± 0.032(syst), F0 = 0.720 ± 0.039 (stat) ± 0.037(syst), and FR = −0.018 ± 0.019 (stat) ± 0.011(syst). These results are used to set limits on the real part of the tWb anomalous couplings, gL and gR.
Electroweak interaction, Hadron-Hadron Scattering, Nuclear and High Energy Physics.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/309398
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