论文标题
迈向中性s $β$衰减的完整前阶预测
Towards complete leading-order predictions for neutrinoless double $β$ decay
论文作者
论文摘要
两$β$（$0νβ$）的中性s衰变的振幅，$ nn \ $ nn \ to ppe^-e^ - $，构成了大型$0νββ$搜索中使用的重核的核结构计算的关键基础。假设$0νβ$工艺是由光 - 摩纳拉纳 - 中诺交换介导的，那么手性有效野外理论的系统分析表明，在领先顺序上已经需要接触式操作员来确保重降低。在这项工作中，我们开发了一种方法来估计其系数的数值以类似于Cottingham公式，并通过重现对核素核子散射长度的荷属不依赖性的贡献来验证结果。我们的中心结果虽然在$ \ operline {\ text {ms}} $方案中得出，但是根据重新归一致的振幅$ \ m nathcal {a}_ν（| \ mathbf {p} |，| \ mathbf {p}^\ prime |）匹配的核定，以确定一个核定的核定，以确定一个核定，以确定一个核定，以确定一个核定，以确定一个核定的核定计算。因此，我们的结果大大减少了搜索$0νβ$衰减的搜索的关键不确定性。
The amplitude for the neutrinoless double $β$ ($0νββ$) decay of the two-neutron system, $nn\to ppe^-e^-$, constitutes a key building block for nuclear-structure calculations of heavy nuclei employed in large-scale $0νββ$ searches. Assuming that the $0νββ$ process is mediated by a light-Majorana-neutrino exchange, a systematic analysis in chiral effective field theory shows that already at leading order a contact operator is required to ensure renormalizability. In this work, we develop a method to estimate the numerical value of its coefficient in analogy to the Cottingham formula and validate the result by reproducing the charge-independence-breaking contribution to the nucleon-nucleon scattering lengths. Our central result, while derived in the $\overline{\text{MS}}$ scheme, is given in terms of the renormalized amplitude $\mathcal{A}_ν(|\mathbf{p}|,|\mathbf{p}^\prime|)$, matching to which will allow one to determine the contact-term contribution in regularization schemes employed in nuclear-structure calculations. Our results thus greatly reduce a crucial uncertainty in the interpretation of searches for $0νββ$ decay.
