Model-independent measurement of the W-boson helicity in top-quark decays at D0.

Journal article

We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1 fb(-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 theta(*) 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 costheta(*) distribution finds that the fraction of longitudinal W bosons f(0)=0.425+/-0.166(stat)+/-0.102(syst) and the fraction of right-handed W bosons f(+)=0.119+/-0.090(stat)+/-0.053(syst), which is consistent at the 30% C.L. with the standard model.

Authors: Abazov, V; Abbott, B; Abolins, M; Acharya, B; Adams, M

• Journal: Physical Review Letters
• Volume: 100
• Issue: 6
• Pages: 062004
• Publication date: 2008-02-01
• DOI: 10.1103/physrevlett.100.062004
• EISSN: 1079-7114
• ISSN: 0031-9007
• Language: English
• Keywords: D0 Collaboration