Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany.
Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia.
Phys Rev Lett. 2014 Jun 6;112(22):221802. doi: 10.1103/PhysRevLett.112.221802. Epub 2014 Jun 4.
A massive, but light, Abelian U(1) gauge boson is a well-motivated possible signature of physics beyond the standard model of particle physics. In this Letter, the search for the signal of such a U(1) gauge boson in electron-positron pair production at the spectrometer setup of the A1 Collaboration at the Mainz Microtron is described. Exclusion limits in the mass range of 40 MeV/c^{2} to 300 MeV/c^{2}, with a sensitivity in the squared mixing parameter of as little as ε^{2}=8×10^{-7} are presented. A large fraction of the parameter space has been excluded where the discrepancy of the measured anomalous magnetic moment of the muon with theory might be explained by an additional U(1) gauge boson.
一个巨大但轻的阿贝尔 U(1)规范玻色子是超出粒子物理学标准模型的物理的一个很好的潜在信号。在这封信中，描述了在美因茨微环（Mainz Microtron）的 A1 合作组的谱仪装置中，通过正负电子对产生来寻找这种 U(1)规范玻色子信号的实验。给出了在 40 MeV/c^{2}到 300 MeV/c^{2}质量范围内的排除限制，在平方混合参数灵敏度方面小到 ε^{2}=8×10^{-7}。在很大一部分参数空间中，已经排除了可能通过额外的 U(1)规范玻色子来解释μ子的测量反常磁矩与理论之间的差异。
