Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27516-3255, USA.
Department of Physics, University of California, Berkeley, California 94720, USA.
Phys Rev Lett. 2018 Oct 26;121(17):172501. doi: 10.1103/PhysRevLett.121.172501.
Observation of neutrinoless double beta decay, a lepton number violating process that has been proposed to clarify the nature of neutrino masses, has spawned an enormous world-wide experimental effort. Relating nuclear decay rates to high-energy, beyond the standard model (BSM) physics requires detailed knowledge of nonperturbative QCD effects. Using lattice QCD, we compute the necessary matrix elements of short-range operators, which arise due to heavy BSM mediators, that contribute to this decay via the leading order π^{-}→π^{+} exchange diagrams. Utilizing our result and taking advantage of effective field theory methods will allow for model-independent calculations of the relevant two-nucleon decay, which may then be used as input for nuclear many-body calculations of the relevant experimental decays. Contributions from short-range operators may prove to be equally important to, or even more important than, those from long-range Majorana neutrino exchange.
中微子无中微子双β衰变的观测，这一过程被提出是为了澄清中微子质量的性质，已经引发了全世界范围内的巨大实验努力。将核衰变率与高能、超越标准模型（BSM）物理联系起来，需要对非微扰 QCD 效应有详细的了解。我们使用格点 QCD 计算了由于重 BSM 介体而出现的短程算子的必要矩阵元，这些算子通过主导阶 π^{-}→π^{+}交换图对这种衰变作出贡献。利用我们的结果并利用有效场论方法，可以对相关的两核衰变进行无模型计算，然后将其用作相关实验衰变的核多体计算的输入。短程算子的贡献可能与长程马约拉纳中微子交换一样重要，甚至可能更重要。
