New interactions perturbing beta neutrino correlations

利用TRIUMF的核衰变原子阱（TRINAT），我们测量了37K中与核自旋有关的β不对称性，Abeta为-0.5707+-0.0019。这是在任何原子核或中子中最精确的-不对称测量，并且与粒子物理学标准模型的预测一致。***目前，Abeta的标准模型预测受到两种允许的算子（Fermi和Gamow-Teller）相对贡献的实验确定的限制。我们寻求两个观测值的改进，这两个观测值依赖于各种衰变产物的动量，并且独立于费米/伽莫夫-泰勒比。我们的项目拨款和去年的RTI正在实施能量依赖Abeta，以改进自旋极化，并升级该实验以接受低能量的beta。******因此，我们寻求将RTI改进为真空离子检测仪器，以便对单极反冲核的自旋不对称性进行新的和互补的实验，以及更少依赖于理论修正的β -反冲巧合。单粒子的反冲不对称将具有非常高的统计量，并且有望在某些类型的相互作用上比现有的β衰变测量提高一个数量级的灵敏度。***我们的新加拿大硕士学生将在仪器硕士学位中使用这些设备，这将导致这些实验的博士项目。我们将继续为一个本科生提供机会，帮助我们开发仪器并学习背景物理。****** *我们也希望在辐射衰变中开始一个时间反转违逆的实验。这种3个动量的相关性不涉及自旋，从涉及自旋的实验（如电偶极矩搜索）中放松了对它的限制。我们正在申请资金购买简单的伽马射线探测器，以增加到现有的TRINAT设备

Using TRIUMF's atom trap for nuclear beta decay (TRINAT), we have measured the beta asymmetry with respect to the nuclear spin in 37K, Abeta, to be -0.5707+-0.0019. This is the most accurate beta asymmetry measurement in any nucleus or the neutron, and is in agreement with the prediction of the Standard Model of particle physics.***The standard model prediction for Abeta is presently limited by experimental determination of the relative contributions of the two allowed operators, Fermi and Gamow-Teller. We seek improvements of two observables that depend on the momentum of the various decay products, and are independent of the Fermi/Gamow-Teller ratio. The energy dependence Abeta[Ebeta] is being implemented from our project grant and last year's RTI to improve the spin polarization and upgrade this experiment to accept lower-energy betas.****** We thus seek improvements in this RTI to in-vacuum ion detection instrumentation to enable a new and complementary experiment on the spin asymmetry of the recoiling nuclei in singles, along with beta-recoil coincidences that are even less dependent on theoretical corrections. The recoil asymmetry in singles would have very high statistics, and holds the promise of an order of magnitude improvement in sensitivity over existing beta decay measurements to certain types of interactions. *** Our new Canadian M.Sc. student would implement this equipment for an instrumental M.Sc., which should lead to a Ph.D. project on these experiments. We continue to provide opportunities to one undergrad at a time to help us develop the instrumentation and learn the background physics.****** *We also wish to begin an experiment in time-reversal violation in radiative beta decay. This correlation of 3 momenta does not involve spin, relaxing constraints on it from experiments involving spin (like electric dipole moment searches). We are applying for funds for simple gamma-ray detectors to add to the present TRINAT apparatus.**