CMS collaboration (2142 authors)Hollar, JonathanNayak, ArunaBargassa, PedrameBeirão Da Cruz E Silva, CristóvãoFaccioli, PietroFerreira Parracho, Pedro GuilhermeGallinaro, MicheleLloret Iglesias, LaraNguyen, FedericoRodrigues Antunes, JoaoSeixas, JoaoVarela, JoaoVischia, PietroDavid Tinoco Mendes, AndreMusella, PasqualeSilva, PedroPela, JoaoLeonardo, Nuno2019-02-042019-02-042015-01-12http://dx.doi.org/10.1007/JHEP01(2015)053http://hdl.handle.net/10400.26/26700A 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 ± 0.028 (stat) ± 0.032(syst), F$_{0}$ = 0.720 ± 0.039 (stat) ± 0.037(syst), and F$_{R}$ = −0.018 ± 0.019 (stat) ± 0.011(syst). These results are used to set limits on the real part of the tWb anomalous couplings, g$_{L}$ and g$_{R}$.engjournal article2019-02-04