Direct observation of longitudinally polarised W± bosons

Acciarri, M. ; Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; Gurtu, A. ; et., al (2000) Direct observation of longitudinally polarised W± bosons Physics Letters B, 474 (1-2). pp. 194-204. ISSN 0370-2693

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The three different helicity states of W± bosons, produced in the reaction e +e - →W+W-→ℓ νqq̅are studied using leptonic and hadronic W decays at √s=183GeV and 189 GeV. The W polarisation is also measured as a function of the scattering angle between the W- − and the direction of the e- beam. The analysis demonstrates that W bosons are produced with all three helicities, the longitudinal and the two transverse states. Combining the results from the two center-of-mass energies and with leptonic and hadronic W decays, the fraction of longitudinally polarised W± bosons is measured to be 0.261 ± 0.051(stat.) ± 0.016(syst.) in agreement with the expectation from the Standard Model.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
ID Code:84056
Deposited On:24 Feb 2012 05:34
Last Modified:24 Feb 2012 05:34

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