/ hep-ex CMS-TOP-12-020

Measurement of the W boson helicity in events with a single reconstructed top quark in pp collisions at $\sqrt{s}$ = 8 TeV

Pages: 33

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 $F_L = 0.298 \pm 0.028 \mathrm{(stat)} \pm 0.032 \mathrm{(syst)}$, $F_0 = 0.720 \pm 0.039 \mathrm{(stat)} \pm 0.037 \mathrm{(syst)}$, and $F_R = - 0.018 \pm 0.019 \mathrm{(stat)} \pm 0.011 \mathrm{(syst)}$. These results are used to set limits on the real part of the tWb anomalous couplings, $g_L$ and $g_R$.

Note: Submitted to JHEP

Total numbers of views: 1136
Numbers of unique views: 517