Helicity of the W boson in lepton +jets t ¯t events

DO Collaboration, The and Bertram, Iain A. and Borissov, Guennadi V. and Ratoff, Peter N. and Sopczak, Andre (2005) Helicity of the W boson in lepton +jets t ¯t events. Physics Letters B, 617 (1-2). pp. 1-10. ISSN 0370-2693

Abstract

We examine properties of candidate events in lepton + jets final states to establish the helicities of W bosons in t→W+b decays. Our analysis is based on a direct calculation of a probability density for each event to correspond to a final state, as a function of the helicity of the W boson. Using the 125 events/pb of data collected by the DØ experiment at the Fermilab Tevatron Collider at , we obtain a longitudinal helicity fraction F0=0.56±0.31, consistent with the prediction of F0=0.70 from the standard model.