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 1fb-1 sample of candidate tt̄ events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron pp̄ Collider. We reconstruct the angle θ* b...
Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , |
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Format: | Journal article |
Language: | English |
Published: |
2008
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Summary: | We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1fb-1 sample of candidate tt̄ events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron pp̄ Collider. We reconstruct the angle θ* 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 θ* distribution finds that the fraction of longitudinal W bosons f0=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. © 2008 The American Physical Society. |
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