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. |