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

Journal Article · Thu Nov 01 04:00:00 EDT 2007

OSTI ID:921117

Abazov, V M

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 Laboratory (FNAL), Batavia, IL
• 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
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DECAY
DISTRIBUTION
Experiment-HEP
FERMILAB TEVATRON
FERMIONS
HELICITY
INTERMEDIATE BOSONS
LEPTONS
STANDARD MODEL
T QUARKS