2007/11/30 by D0 Collaboration, B. Abbott, V. M. Abazov +97 · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex
paper · pdf · doi:10.1103/physrevlett.100.062004
published as Phys.Rev.Lett.100:062004,2008 · submitted to Phys. Rev. Lett
arxiv created 2007/12/12 · openalex publication_date 2008/02/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1 fb^\ensuremath-1 sample of candidate tt events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron pp Collider. We reconstruct the angle \ensuremathθ* between the momenta of the down-type fermion and the top quark in the W boson rest frame for each top quark decay. A fit of the resulting cos\ensuremathθ* distribution finds that the fraction of longitudinal W bosons f0=0.425\ifmmode±\else\textpm\fi0.166(stat)\ifmmode±\else\textpm\fi0.102(syst) and the fraction of right-handed W bosons f+=0.119\ifmmode±\else\textpm\fi0.090(stat)\ifmmode±\else\textpm\fi0.053(syst), which is consistent at the 30% C.L. with the standard model.