School of Physics, Peking University, Beijing 100871, China.
Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
Phys Rev Lett. 2019 Jan 18;122(2):022001. doi: 10.1103/PhysRevLett.122.022001.
We present an exploratory lattice QCD calculation of the neutrinoless double beta decay ππ→ee. Under the mechanism of light-neutrino exchange, the decay amplitude involves significant long-distance contributions. The calculation reported here, with pion masses m_{π}=420 and 140 MeV, demonstrates that the decay amplitude can be computed from first principles using lattice methods. At unphysical and physical pion masses, we obtain that amplitudes are 24% and 9% smaller than the predication from leading order chiral perturbation theory. Our findings provide the lattice QCD inputs and constraints for effective field theory. A follow-on calculation with fully controlled systematic errors will be possible with adequate computational resources.
我们提出了一个探索性的格点 QCD 计算，研究中微子双 β 衰变 ππ→ee。在轻中微子交换的机制下，衰变振幅涉及到显著的远距离贡献。这里报告的计算，使用介子质量 m_{π}=420 和 140 MeV，表明可以使用格点方法从第一性原理计算衰变振幅。在非物理和物理介子质量下，我们得到的振幅比领头阶手征微扰理论的预测小 24%和 9%。我们的发现为有效场论提供了格点 QCD 的输入和约束。在有足够计算资源的情况下，通过完全控制系统误差的后续计算将成为可能。
