BESⅢ合作组最近开始双光子物理研究,主要源于强子light-by-light散射对缪子反常磁矩的贡献有很大不确定性,电磁跃迁形状因子作为实验输入是改善计算精度的需要。在BESⅢ探测器上获得的质心能量3.77 Ge V到4.6Ge V的数据使得我们能够测...BESⅢ合作组最近开始双光子物理研究,主要源于强子light-by-light散射对缪子反常磁矩的贡献有很大不确定性,电磁跃迁形状因子作为实验输入是改善计算精度的需要。在BESⅢ探测器上获得的质心能量3.77 Ge V到4.6Ge V的数据使得我们能够测量轻赝标量介子的跃迁形状因子。在动量转移低于2(Ge V/c)2时单标记技术测量的结果达到前所未有的精确,该区域对于αμ的计算十分重要,并且也首次开始了π介子跃迁形状因子的双标记测量。这是π~0跃迁形状因子模型无关参数化研究的第一步。另外,多介子末态测量也在进行中.展开更多
The hadronic corrections to the muon anomalous magnetic moment αμ,due to the full gaugeinvariant set of diagrams with dynamical quark loop and intermediate pseudoscalar and scalar states lightby-light scattering ins...The hadronic corrections to the muon anomalous magnetic moment αμ,due to the full gaugeinvariant set of diagrams with dynamical quark loop and intermediate pseudoscalar and scalar states lightby-light scattering insertions,are calculated in the framework of the nonlocal chiral quark model. These diagrams correspond to all hadronic light-by-light scattering contributions to α_μ in the leading order of the1 / N_c expansion in quark model. The result of the quark loop contribution is α_μ^(HLbL,Loop)=(11. 0 ± 0. 9) ·10^(-10),and the total result is α_μ^(HLbL,Loop)=(16.8 ± 1.2) ·10^(-10).展开更多
基金Supported by the German Research Foundation DFG under Contract(CRC-1044)
文摘BESⅢ合作组最近开始双光子物理研究,主要源于强子light-by-light散射对缪子反常磁矩的贡献有很大不确定性,电磁跃迁形状因子作为实验输入是改善计算精度的需要。在BESⅢ探测器上获得的质心能量3.77 Ge V到4.6Ge V的数据使得我们能够测量轻赝标量介子的跃迁形状因子。在动量转移低于2(Ge V/c)2时单标记技术测量的结果达到前所未有的精确,该区域对于αμ的计算十分重要,并且也首次开始了π介子跃迁形状因子的双标记测量。这是π~0跃迁形状因子模型无关参数化研究的第一步。另外,多介子末态测量也在进行中.
基金Supported by by Russian Science Foundation(14-50-00080)RFBR grant(15-02-03391)
文摘The hadronic corrections to the muon anomalous magnetic moment αμ,due to the full gaugeinvariant set of diagrams with dynamical quark loop and intermediate pseudoscalar and scalar states lightby-light scattering insertions,are calculated in the framework of the nonlocal chiral quark model. These diagrams correspond to all hadronic light-by-light scattering contributions to α_μ in the leading order of the1 / N_c expansion in quark model. The result of the quark loop contribution is α_μ^(HLbL,Loop)=(11. 0 ± 0. 9) ·10^(-10),and the total result is α_μ^(HLbL,Loop)=(16.8 ± 1.2) ·10^(-10).
