Measurement of the W boson helicity in top quark decays at D0

Journal Article · Thu Feb 01 04:00:00 EST 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.75.031102· OSTI ID:21010959

Abazov, V M; Alexeev, G D; Kalinin, A M; Kharzheev, Y M; Malyshev, V L; Tokmenin, V V; Vertogradov, L S; Yatsunenko, Y A ^[1]; Abbott, B; Gutierrez, P; Hall, I; Jain, S; Kopal, M; Pompos, A; Severini, H; Skubic, P; Strauss, M ^[2]; Abolins, M; Benitez, J A; Brock, R ^[3]

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1. Joint Institute for Nuclear Research, Dubna (Russian Federation)
2. University of Oklahoma, Norman, Oklahoma 73019 (United States)
3. Michigan State University, East Lansing, Michigan 48824 (United States)

We present a measurement of the fraction f{sub +} of right-handed W bosons produced in top quark decays, based on a candidate sample of tt events in the l+jets and dilepton decay channels corresponding to an integrated luminosity of 370 pb{sup -1} collected by the D0 detector at the Fermilab Tevatron pp Collider at {radical}(s)=1.96 TeV. We reconstruct the decay angle {theta}* for each lepton. By comparing the cos{theta}* distribution from the data with that for the expected background and signal for various values of f{sub +} (where we assume that the fraction of longitudinally-polarized W bosons has the standard model value of 0.70), we find f{sub +}=0.056{+-}0.080(stat){+-}0.057(syst) (f{sub +}<0.23 at 95% C.L.), consistent with the standard model prediction of f{sub +}=3.6x10{sup -4}.

• OSTI ID: 21010959
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 3 Vol. 75; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COMPARATIVE EVALUATIONS
DISTRIBUTION
FERMILAB TEVATRON
HELICITY
JET MODEL
LEPTONS
PARTICLE DECAY
STANDARD MODEL
T QUARKS
TEV RANGE
W MINUS BOSONS
W PLUS BOSONS