Benayoun M, DelBuono L, Jegerlehner F
LPNHE des Universités Paris VI et Paris VII, IN2P3/CNRS, 75252 Paris, France.
Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, 12489 Berlin, Germany.
Eur Phys J C Part Fields. 2022;82(2):184. doi: 10.1140/epjc/s10052-022-10096-4. Epub 2022 Feb 28.
The generic hidden local symmetry (HLS) model has recently given rise to its variant, defined by introducing symmetry breaking mostly in the vector meson sector; the central mechanism is a modification of the covariant derivative at the root of the HLS approach. However, the description of the dipion spectra, especially the Belle one, is not fully satisfactory, whereas the simultaneous dealing with its annihilation sector ( ) is optimum. We show that this issue is solved by means of an additional breaking term which also allows us to consistently include the mixing properties of the system within this extended ( ) scope. This mechanism, an extension of the usual 't Hooft determinant term, only affects the kinetic energy part of the Lagrangian. One thus obtains a fair account for the dipion spectra which complements the fair account of the annihilation channels already reached. The Belle dipion spectrum is found to provide evidence in favor of a violation of the conserved vector current (CVC) in the lepton decay; this evidence is enforced by imposing the conditions on axial current matrix elements. is found to recover the usual (completed) formulae for the [ ] mixing parameters, and the global fits return mixing parameter values in agreement with expectations and better uncertainties. Updating the muon hadronic vacuum polarization (HVP), one also argues that the strong tension between the KLOE and BaBar pion form factors imposes to provide two solutions, namely and , in units of , rather than some combination of these. Taking into account common systematics, their differences from the experimental BNL-FNAL average value exhibit significance (KLOE) and (BaBar), with fit probabilities favoring the former.
通用的隐藏局域对称性（HLS）模型最近产生了其变体，主要通过在矢量介子部分引入对称性破缺来定义；核心机制是对HLS方法根源处的协变导数进行修改。然而，双π介子谱的描述，尤其是 Belle 实验的数据，并不完全令人满意，而同时处理其湮灭部分（ ）则是最优的。我们表明，通过一个额外的破缺项可以解决这个问题，这也使我们能够在这个扩展的（ ）范围内一致地纳入 系统的混合特性。这种机制是通常的‘t Hooft 行列式项的扩展，仅影响 拉格朗日量的动能部分。这样就得到了对双π介子谱的合理描述，它补充了已经得到的对湮灭通道的合理描述。发现 Belle 双π介子谱为轻子衰变中守恒矢量流（CVC）的违反提供了证据；通过对轴矢流矩阵元施加条件，这一证据得到了加强。发现 恢复了[ ]混合参数的通常（完整）公式，全局拟合返回的混合参数值与预期一致且不确定性更小。更新μ子强子真空极化（HVP）后，人们还认为 KLOE 和 BaBar 介子形状因子之间的强烈张力要求提供两个以 为单位的解，即 和 ，而不是它们的某种组合。考虑到共同的系统误差，它们与实验 BNL - FNAL 平均值的差异在 KLOE 实验中显示出显著性 ，在 BaBar 实验中显示出显著性 ，拟合概率更倾向于前者。
