Correlations between polarisation states of W particles in the reaction e-e+→W-W+ at LEP2 energies 189-209 GeV
- Journal Article
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In a study of the reaction e − e +→W − W + with the DELPHI detector, the probabilities of the two W particles occurring in the joint polarisation states transverse–transverse (TT), longitudinal–transverse plus transverse–longitudinal (LT) and longitudinal–longitudinal (LL) have been determined using the final states WW→lνqq¯ (l=e,μ). The two-particle joint polarisation probabilities, i.e. the spin density matrix elements ρ TT , ρ LT , ρ LL , are measured as functions of the W − production angle, θW−, at an average reaction energy of 198.2 GeV. Averaged over all cosθW−, the following joint probabilities are obtained: ρ¯TT=(67±8)%, ρ¯LT=(30±8)%, ρ¯LL=(3±7)%. These results are in agreement with the Standard Model predictions of 63.0%, 28.9% and 8.1%, respectively. The related polarisation cross-sections σ TT , σ LT and σ LL are also presented. Show more
Journal / seriesThe European Physical Journal C
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