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## Measurement of the W boson helicity in top quark decay at D0

### Abstract

Submitted to Phys. Rev. Lett - D0We present a measurement of the fraction f_+ of right-handed W bosons produced in top quark decays, based on a candidate sample of ttbar events in the l+jets and dilepton decay channels corresponding to an integrated luminosity of 370 pb^-1 collected by the DO detector at the Fermilab Tevatron ppbar Collider at sqrt{s}=1.96 TeV. We reconstruct the decay angle theta^* for each lepton. By comparing the \cos\theta^* distribution from the data with those for the expected background and signal for various values of f_+, we find \$f_+=0.056 +- 0.080 (stat) +- 0.057 (syst)}. (f_+ < 0.23 at 95% C.L.), consistent with the standard model prediction of f_+=3.6 x10^-4

Topics: [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex]
Publisher: American Physical Society
Year: 2007
DOI identifier: 10.1103/PhysRevD.75.031102
OAI identifier: oai:HAL:in2p3-00101469v1
Provided by: Hal-Diderot