Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands.
University of California at Santa Barbara, Santa Barbara, California 93106, USA.
Nature. 2017 Jun 7;546(7657):227-233. doi: 10.1038/nature22346.
One of the key assumptions of the standard model of particle physics is that the interactions of the charged leptons, namely electrons, muons and taus, differ only because of their different masses. Whereas precision tests comparing processes involving electrons and muons have not revealed any definite violation of this assumption, recent studies of B-meson decays involving the higher-mass tau lepton have resulted in observations that challenge lepton universality at the level of four standard deviations. A confirmation of these results would point to new particles or interactions, and could have profound implications for our understanding of particle physics.
粒子物理学标准模型的一个关键假设是，带电轻子（即电子、μ 子和τ 子）的相互作用仅因质量不同而有所差异。虽然比较涉及电子和μ 子的过程的精度测试尚未发现该假设的任何明确违反，但最近对涉及更高质量τ 轻子的 B 介子衰变的研究结果表明，在四个标准差的水平上挑战了轻子普遍性。这些结果的证实将指向新的粒子或相互作用，并可能对我们对粒子物理学的理解产生深远影响。
