Institute for High Energy Physics, Protvino 142281.
High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801.
Phys Rev Lett. 2014 Jan 24;112(3):031801. doi: 10.1103/PhysRevLett.112.031801. Epub 2014 Jan 23.
The lifetime of the τ lepton is measured using the process e+ e- → τ+ τ- , where both τ leptons decay to 3πν(τ). The result for the mean lifetime, based on 711 fb(-1) of data collected with the Belle detector at the ϒ(4S) resonance and 60 MeV below, is τ=(290.17±0.53(stat)±0.33(syst))×10(-15) s. The first measurement of the lifetime difference between τ+ and τ- is performed. The upper limit on the relative lifetime difference between positive and negative τ leptons is |Δτ|/τ<7.0×10(-3) at 90% C.L.
τ 轻子的寿命是通过 e+ e- → τ+ τ- 过程来测量的，其中两个 τ 轻子都衰变为 3πν(τ)。基于 Belle 探测器在 Y(4S)共振处和 60 MeV 以下收集的 711 fb(-1)数据，τ 的平均寿命结果为 τ=(290.17±0.53(stat)±0.33(syst))×10(-15) s。首次测量了 τ+ 和 τ- 的寿命差异。在 90%置信水平下，正、负 τ 轻子的相对寿命差异的上限为 |Δτ|/τ<7.0×10(-3)。
