Direct observation of longitudinally polarised W±bosons

L3 Collaboration

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The three different helicity states of W ± bosons, produced in the reaction e+ e- → W+W- →lvqq̄ are studied using leptonic and hadronic W decays at √s = 183 GeV 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.

Original languageEnglish (US)
Pages (from-to)194-204
Number of pages11
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number1-2
StatePublished - Feb 10 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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