论文标题
$β$衰减频谱的$^6 $ He
Ab initio calculation of the $β$ decay spectrum of $^6$He
论文作者
论文摘要
我们使用量子蒙特卡洛方法计算$β$频谱在$^6 $的衰减中，其具有源自手性有效场理论的核相互作用以及一致的弱矢量和轴向电流。我们在多极扩展中以二阶工作，保留了由$ \ Mathcal O（q^2/m_π^2）$抑制的术语，其中$ q $表示诸如反应的$ \ MATHCAL Q $ value或Electron和electron和$m_π$ pion pion smos等低能尺度。通过包括两体矢量和轴向电流的影响，我们超越了脉冲近似。我们通过在诺福克家族中使用四个潜在模型来估算频谱上的理论误差，这些模型具有不同的截止和三核的相互作用，它们具有不同的截止，将两核子数据拟合到不同的能量，并使用不同的观察力来确定三体力的耦合。我们发现，按总率归一化的$β$频谱的理论不确定性远低于透过的水平，并从多极扩展中的一阶和二阶校正中获得了可比大小的贡献。我们考虑对标准模型有效场理论中的超越标准模型充电相互作用引起的$β$衰变光谱的校正，并具有无菌中微子，并讨论了下一代实验对这些相互作用的敏感性。
We calculate the $β$ spectrum in the decay of $^6$He using Quantum Monte Carlo methods with nuclear interactions derived from chiral Effective Field Theory and consistent weak vector and axial currents. We work at second order in the multipole expansion, retaining terms suppressed by $\mathcal O(q^2/m_π^2)$, where $q$ denotes low-energy scales such as the reaction's $\mathcal Q$-value or the electron energy, and $m_π$ the pion mass. We go beyond the impulse approximation by including the effects of two-body vector and axial currents. We estimate the theoretical error on the spectrum by using four potential models in the Norfolk family of local two- and three-nucleon interactions, which have different cut-off, fit two-nucleon data up to different energies and use different observables to determine the couplings in the three-body force. We find the theoretical uncertainty on the $β$ spectrum, normalized by the total rate, to be well below the permille level, and to receive contributions of comparable size from first and second order corrections in the multipole expansion. We consider corrections to the $β$ decay spectrum induced by beyond-the-Standard Model charged-current interactions in the Standard Model Effective Field Theory, with and without sterile neutrinos, and discuss the sensitivity of the next generation of experiments to these interactions.
