Laboratoire d'Annecy-le-Vieux de Physique des Particules, Université de Savoie, CNRS/IN2P3, F-74941 Annecy-Le-Vieux, France.
Phys Rev Lett. 2010 Apr 16;104(15):151802. doi: 10.1103/PhysRevLett.104.151802.
Charged-lepton flavor-violating processes are unobservable in the standard model, but they are predicted to be enhanced in several extensions to the standard model, including supersymmetry and models with leptoquarks or compositeness. We present a search for such processes in a sample of 99x10(6)Upsilon(2S) decays and 117x10(6)Upsilon(3S) decays collected with the BABAR detector. We place upper limits on the branching fractions B(Upsilon(nS)-->e(+/-)tau(-/+)) and B(Upsilon(nS)-->mu(+/-)tau(-/+)) (n=2,3) at the 10(-6) level and use these results to place lower limits of order 1 TeV on the mass scale of charged-lepton flavor-violating effective operators.
带电荷轻子味破坏过程在标准模型中不可观测，但在标准模型的几种扩展中，包括超对称和具有轻夸克或复合性的模型，它们被预言会增强。我们在 BABAR 探测器收集的 99x10(6)Upsilon(2S)衰变和 117x10(6)Upsilon(3S)衰变样本中，对这些过程进行了搜索。我们在 10(-6)水平上对分支比 B(Upsilon(nS)-->e(+/-)tau(-/+))和 B(Upsilon(nS)-->mu(+/-)tau(-/+))(n=2,3) 施加了上限，并使用这些结果对带电荷轻子味破坏有效算子的质量标度施加了约 1 TeV 的下限。
