Measurement of the W boson helicity fractions in the decays of top quark pairs to lepton?+?jets final states produced in pp collisions at s=8TeV
Journal
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Journal Volume
762
Pages
512-534
Date Issued
2016
Abstract
The W boson helicity fractions from top quark decays in tt events are measured using data from protonproton collisions at a centre-of-mass energy of 8 TeV. The data were collected in 2012 with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb -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 F 0 = 0.681 0.012 (stat) 0.023 (syst), F L = 0.323 0.008 (stat) 0.014 (syst), and F R = -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.
SDGs
Type
journal article