格点QCD给出的无中微子双β衰变的长程核矩阵元
Long-Distance Nuclear Matrix Elements for Neutrinoless Double-Beta Decay from Lattice QCD
AI总结：
本工作首次利用格点QCD计算了多核子系统中由轻马约拉纳中微子介导的无中微子双β衰变矩阵元，并探讨了与有效场论匹配以确定低能常数的前景，为未来物理参数下的理论计算奠定基础。
摘要：
无中微子双β（$0νββ$）衰变是一个迄今为止未被观测到的过程，如果被观测到，将意味着中微子是马约拉纳粒子。对$0νββ$衰变半衰期的严格实验约束的解释需要计算核矩阵元。本工作首次给出了多核子系统中$0νββ$衰变矩阵元的格点量子色动力学（LQCD）计算，具体为在核尺度距离上传播的轻左手马约拉纳中微子介导的$nn \ ightarrow pp ee$跃迁。该计算是在对应于$m_π= 806$ MeV的π子质量的夸克质量下，在单一格点间距和体积下进行的。为了研究各种系统不确定性，还计算了统计上更干净的$Σ^- \ ightarrow Σ^+ ee$跃迁。研究了将LQCD计算结果匹配到核有效场论上，以确定与具有轻马约拉纳中微子的$0νββ$衰变相关的领头阶低能常数的前景。因此，这项工作为未来在夸克质量的物理值下进行计算奠定了基础，这些计算与有效场论和核多体研究相结合，将为$0νββ$衰变的实验搜索提供受控的理论输入。
英文摘要：
Neutrinoless double-beta ($0νββ$) decay is a heretofore unobserved process which, if observed, would imply that neutrinos are Majorana particles. Interpretations of the stringent experimental constraints on $0νββ$-decay half-lives require calculations of nuclear matrix elements. This work presents the first lattice quantum-chromodynamics (LQCD) calculation of the matrix element for $0νββ$ decay in a multi-nucleon system, specifically the $nn \rightarrow pp ee$ transition, mediated by a light left-handed Majorana neutrino propagating over nuclear-scale distances. This calculation is performed with quark masses corresponding to a pion mass of $m_π= 806$ MeV at a single lattice spacing and volume. The statistically cleaner $Σ^- \rightarrow Σ^+ ee$ transition is also computed in order to investigate various systematic uncertainties. The prospects for matching the results of LQCD calculations onto a nuclear effective field theory to determine a leading-order low-energy constant relevant for $0νββ$ decay with a light Majorana neutrino are investigated. This work, therefore, sets the stage for future calculations at physical values of the quark masses that, combined with effective field theory and nuclear many-body studies, will provide controlled theoretical inputs to experimental searches of $0νββ$ decay.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
