Download or read book Combination of CDF and D0 Measurements of the $W$ Boson Helicity in Top Quark Decays written by and published by . This book was released on 2012 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 p{bar p} 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.