Cross sections and charge asymmetries for e+e−→μ+μ− and e+e−→τ+τ−reactions at

• DOI: 10.1016/0370-2693(92)90145-t
• Publication Date: 2002-11-12T11:13:41Z
• Authors: B. Howell; D. Koltick; T. Tauchi; A. Miyamoto; H. Kichimi; K. Fujii; T. Abe; I. Adachi; M. Aoki; R. Belusevic; M. Doser; K. Emi; R. Enomoto; H. Fujii; T. Fujii; J. Fujimoto; N. Fujiwara; K. Harigae; H. Hayashii; N. Iida; H. Ikeda; R. Itoh; M. Iwasaki; H. Iwasaki; R. Rajikawa; S. Kato; S. Kawabata; T. Kishida; M. Kobayashi; I. Levine; K. Miyabayashi; K. Muramatsu; K. Nagai; T. Nagira; E. Nakano; M. Nakayama; O. Nitoh; S. Noguchi; F. Ochiaj; Y. Ohnishi; H. Okuno; T. Okusawa; E. Sakai; A. Shimonaka; K. Shimozawa; A. Shirahashi; A. Sugiyama; N. Sugiyama; S. Suzuki; N. Tachibana; K. Takahashi; T. Takahashi; M. Takemoto; T. Tanimori; F. Teramae; Y. Teramoto; T. Toyama; T. Tsukamoto; S. Uno; Y. Watanabe; A. Yamamoto; S. Yamamoto; M. Yamauchi
• Keywords: Topaz; Electron–positron annihilation

The process e+e−→μ+μ−and e+e− have been studied in the energy range s=52−61.4 GeV, using the TOPAZ detector at TRISTAN. From an integrated luminosity of L = 74.0 pb−1, lowest-order cross sections and forward-backward asymmetries are measured to be 〈σμμ〈 = 25.4±0.9±1.2 pb, 〈Aμμ〉 = (−32.2±3.1±1.1)%, 〈σττ〉 = 27.1±1.1±1.2 pb, 〈Aττ〉 = (−33.9±4.9±1.0)% , at an average energy of s〉=57.87 GeV. From the measured assymetry we derive axial vector couplings of acaμ=0.96±0.09±0.01,and acaτ=1.01±0.14±0.01±. These results are consistent with standard model expectations. Lower limits in the range 2–5 TeV (95%CL)are placed on compositeness scale parameters for leptons.