par Khachatryan, Vardan;Brun, Hugues ;Caillol, Cécile ;Clerbaux, Barbara ;De Lentdecker, Gilles ;Delannoy, Hugo ;Fasanella, Giuseppe ;Favart, Laurent ;Goldouzian, Reza ;Grebenyuk, Anastasia ;Karapostoli, Georgia ;Lenzi, Thomas ;Leonard, Alexandre ;Luetic, Jelena ;Maerschalk, Thierry ;Marinov, Audrey ;Randle-Conde, Aidan Sean ;Seva, Tomislav ;Vander Velde, Catherine ;Vanlaer, Pascal ;Yonamine, Ryo ;Zenoni, Florian ;Zhang, Fengwangdong ;Fang, Wenxing ; [et al.]
Référence Physics letters. Section B, 762, page (512-534)
Publication Publié, 2016
Référence Physics letters. Section B, 762, page (512-534)
Publication Publié, 2016
Article révisé par les pairs
Résumé : | The W boson helicity fractions from top quark decays in tt‾ events are measured using data from proton–proton collisions at a centre-of-mass energy of 8TeV. The data were collected in 2012 with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8fb−1. Events are reconstructed with either one muon or one electron, along with four jets in the final state, with two of the jets being identified as originating from b quarks. The measured helicity fractions from both channels are combined, yielding F0=0.681±0.012(stat)±0.023(syst), FL=0.323±0.008(stat)±0.014(syst), and FR=−0.004±0.005(stat)±0.014(syst) for the longitudinal, left-, and right-handed components of the helicity, respectively. These measurements of the W boson helicity fractions are the most accurate to date and they agree with the predictions from the standard model. |