Precision Tests of the Standard Model and Low Energy Hadronic Interactions

标准模型和低能强子相互作用的精度测试

• 批准号: SAPIN-2016-00037
• 负责人: Aleksejevs, Aleksandrs
• 金额: $ 1.68万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=617844
• 关键词: Precision; Tests; Standard; Model; Low

Search for physics beyond the Standard Model (BSM) has three major directions: energy, cosmic and precision frontiers. I am interested in the precision frontier driven by the indirect searches, where new particles could impact observables such as scattering cross section or asymmetry causing small deviations from original Standard Model (SM) predictions, and there are several upcoming new-generation, ultra-precise measurements with intense particle beams which could detect such small effect. One of such experiments, MOLLER, studying parity-violating Møller scattering, would allow a determination of the weak mixing angle with an uncertainty of 0.1%, an improvement of a factor of five in fractional precision compared with the previous E-158 measurement. At such precision, any inconsistency with the SM could signal BSM physics. Such precision will require a matching theoretical uncertainty, which can be achieved only by including electroweak calculations up to the two-loop order. We plan to construct Two-Loop Electroweak Computational Model (2L-ECM) for the particles of the Standard Model and calculate the full set of two-loop contributions to the Parity Violating (PV) asymmetry for electron-electron scattering required by the MOLLER experiment. Later, 2L-ECM should be extended to the broad spectrum of processes involving particles of SM. The next stage would be including the various hypothetical BSM particles up to one-loop level, and studying their impact on the electroweak observables.

对标准模型（BSM）之外的物理学的研究有三个主要方向：能量、宇宙和精确前沿。我对间接搜索驱动的精度前沿感兴趣，新粒子可能会影响可观测值，如散射截面或不对称性，导致与原始标准模型（SM）预测的微小偏差，并且有几个即将到来的新一代超精确测量，可以检测到这种微小的影响。其中一个实验，MOLLER，研究宇称违反穆勒散射，将允许确定弱混合角的不确定性为0.1%，与以前的E-158测量相比，分数精度提高了五倍。在如此精确的情况下，任何与SM的不一致都可能表明BSM的物理性质。这样的精度将需要一个匹配的理论不确定性，这只能通过包括电弱计算达到两个回路的顺序。我们计划为标准模型的粒子构建双环电弱计算模型（2L-ECM），并计算MOLLER实验所需的电子-电子散射的宇称破坏（PV）不对称性的全套双环贡献。后来，2L-ECM应该扩展到涉及SM颗粒的广泛过程。下一个阶段将包括各种假设的BSM粒子到一圈水平，并研究它们对电弱可观测量的影响。