Abstract The status of tests of the standard electroweak model and of searches for new physics in allowed nuclear β decay and neutron decay is reviewed including both theoretical and experimental developments. The sensitivity and complementarity of recent and ongoing experiments are discussed with emphasis on their potential to look for new physics. Measurements are interpreted using a model-independent effective field theory approach enabling to recast the outcome of the analysis in many specific new physics models. Special attention is given to the connection that this approach establishes with high-energy physics. A new global fit of available β -decay data is performed incorporating, for the first time in a consistent way, superallowed 0 + → 0 + transitions, neutron decay and nuclear decays. The constraints on exotic scalar and tensor couplings involving left- or right-handed neutrinos are determined while a constraint on the pseudoscalar coupling from neutron decay data is obtained for the first time as well. The values of the vector and axial–vector couplings, which are associated within the standard model to V u d and g A respectively, are also updated. The ratio between the axial and vector couplings obtained from the fit under standard model assumptions is C A ∕ C V = − 1 . 27510 ( 66 ) . The relevance of the various experimental inputs and error sources is critically discussed and the impact of ongoing measurements is studied. The complementarity of the obtained bounds with other low- and high-energy probes is presented including ongoing searches at the Large Hadron Collider.

中文翻译：

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核与中子β衰变的新物理学研究

摘要 回顾了标准电弱模型的测试和在允许的核 β 衰变和中子衰变中寻找新物理的状态，包括理论和实验发展。讨论了最近和正在进行的实验的敏感性和互补性，重点是它们寻找新物理的潜力。使用独立于模型的有效场论方法来解释测量结果，从而能够在许多特定的新物理模型中重铸分析结果。特别注意这种方法与高能物理学建立的联系。对可用 β 衰变数据进行了新的全局拟合，首次以一致的方式结合了超允许的 0 + → 0 + 跃迁、中子衰变和核衰变。确定了对涉及左手或右手中微子的奇异标量和张量耦合的约束，同时也首次获得了对来自中子衰变数据的伪标量耦合的约束。在标准模型中分别与 V ud 和 g A 相关联的矢量和轴向矢量耦合的值也被更新。从标准模型假设下的拟合获得的轴向和矢量耦合之间的比率是 CA ∕ CV = − 1 。27510 (66)。批判性地讨论了各种实验输入和误差源的相关性，并研究了正在进行的测量的影响。所获得的界限与其他低能和高能探针的互补性被呈现出来，包括在大型强子对撞机上正在进行的搜索。