缪子反常磁矩的精确测量预示存在新物理

Precise measurement of muon anomalous magnetic moment

缪子反常磁矩a_(µ)=(g_(µ)-2)/2是缪子的基本物理参数之一,它的精确测量和理论计算为标准模型的诞生奠定了基础。费米缪子反常磁矩实验的首个实验结果表明缪子反常磁矩的测量值和标准模型理论预言不相符。该结果与早期布鲁克海文实验的结果相一致。这2个实验的综合测量结果与标准模型预言值的差距为4.2σ,这为新物理的存在提供了强有力的证据,预示着世界上可能存在新的未知粒子或者作用力。

The muon anomalous magnetic moment a_(µ)=(g_(µ)-2)/2 is a fundamental property of the muon particle,which plays a foundation role in the formation of the Standard Model.The first results of the Fermilab Muon g-2 experiment show that the experimental measurement of aµdeviates with the theoretical prediction by 3.3 standard deviation,as in agreement with the previous measurements from the BNL experiment.The combined result of the two experiments is 4.2 standard deviation away from the Standard Model prediction,which provides a strong evidence for new physics,indicating the existence of possible unknown particles or new forces.