Combination of CDF and D0 measurements of the W boson helicity in top quark decays
Presented by Prof. Erich Ward VARNES on 5 Jul 2012 from 16:30 to 16:45
Type: Parallel Sessions
Session: TR4 - Top Quark Physics
Track: Track 4 - Top Quark Physics
We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7 – 5.4 fb−1 of ppbar collisions collected during Run II of the Fermilab Tevatron Collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f0) and right-handed (f+) helicities, we find f0 = 0.722 ± 0.081 [± 0.062 (stat.) ± 0.052 (syst.)] and f+ = −0.033 ± 0.046 [± 0.034 (stat.) ± 0.031 (syst.)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f0 = 0.682±0.057 [± 0.035 (stat.)±0.046 (syst.)] and f+ = −0.015±0.035 [± 0.018 (stat.)±0.030 (syst.)]. The results are consistent with standard model expectations.