Measurement of Z decays into lepton pairs.
نویسندگان
چکیده
. . We present measurements by the Mark II experiment of the ratios of the leptonic partial widths of the 2 boson to the hadronic partial width. The results are k = 0.037~~$~, & = 0.053’$:4: and k = 0.066~~:$$, in good agreement with the Standard Model prediction of 0.048. From the average leptonic width result, & = 0.053~~.~~~, we derive I’had = 1.56~~.~~ GeV. We find for the vector coupling constants of the tau and muon vz = 0.31 f 0.31 ‘i.5: and ?J; = 0.05 f 0.30 ‘!I;;. PACS numbers: 13.38.+c, 12.15.Ji Submitted to Physical Review Letters .In this Letter we present the first study of 2 boson decays into lepton pairs .c using the Mark II detector at the SLAC Linear Collider. We present the ratio of -. the partial decay width into lepton pairs to the partial decay width into hadrons: rn Br(Z + ZZ) = rhad Br(Z t hadrons) ’ _ which is independent of the center of mass energy. In the Standard Model this ratio is expected’ to be 0.048.
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ورودعنوان ژورنال:
- Physical review letters
دوره 63 26 شماره
صفحات -
تاریخ انتشار 1989