Constraints on Physics Beyond the Standard Model from Lower Energy Electron Scattering

我们建议研究极化电子-C_(12)散射的理论预测。建议在美因茨能量回收超导加速器MESA进行相应的测量。这可以提供对弱混合角的高精度确定，以及对标准模型以外的物理约束。我们的目的是在粒子物理的标准模型中为破坏宇称的极化不对称性奠定理论基础和计算预测，并研究标准模型以外的物理敏感性。我们设想三个相互关联的工作包：A：在标准模型内获得电子-C_(12)散射中宇称破坏自旋不对称性的理论预测，包括由高阶微扰修正和核形状因子效应引起的所有可能的不确定源；B：研究对有效的四费米子算符的敏感性，考虑其他电子(正电子)和中微子散射以及中微子振荡实验的相互作用和影响；C通过应用QCD求和规则来确定夸克质量及其不确定度，从而获得输入到工作包A所需的低能弱混合角计算中的一种成分。

We propose to study theoretical predictions for polarized electron-C12 scattering. A corresponding measurement was suggested to be performed at the Mainz Energy-Recovering Superconducting Accelerator, MESA. This could provide a high-precision determination of the weak mixing angle, as well as constraints on physics beyond the Standard Model. Our aim is to lay out the theoretical foundation and calculate predictions within the Standard Model of particle physics for the parity-violating polarization asymmetry as well as to study the sensitivity to physics beyond the Standard Model. The results obtained from the theoretical work suggested in this research proposal will define the physics case of such a measurement.We envisage three connected work packages: A: To obtain theory predictions within the Standard Model for the parity violating spin asymmetry in electron-C12 scattering including all possible sources of uncertainties due to higher-order perturbative corrections and nuclear form factor effects; B: To study the sensitivity to effective four-fermion operators, taking into account the interplay with and impact on complementary searches of other electron (positron) and neutrino scattering as well as neutrino oscillation experiments; C To determine quark masses and their uncertainties through the application of QCD sum rules and thus obtain one of the ingredients feeding into the calculation of the low-energy weak mixing angle needed within work package A.