Model-independent measurement of the W boson helicity in top quark decays at D0
We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1 fb{sup -1} sample of candidate t{bar t} events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron p{bar p} 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 cos {theta}* distribution finds that the fraction of longitudinal W bosons f{sub 0} = 0.390 {+-} 0.177 (stat.) {+-} 0.104 (syst.) and the fraction of right-handed W bosons f{sub +} = 0.171 {+-} 0.102 (stat.) {+-} 0.058 (syst.), which is consistent at the 27% C.L. with the standard model.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 921117
- Report Number(s):
- FERMILAB-PUB-07-588-E; arXiv eprint number arXiv:0711.0032; TRN: US0801940
- Country of Publication:
- United States
- Language:
- English
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Measurement of the W boson helicity in top quark decay at D0
Measurement of the W boson helicity in top quark decays at D0