Li Gang, Ramsey-Musolf Michael J, Vasquez Juan Carlos
Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Phys Rev Lett. 2021 Apr 16;126(15):151801. doi: 10.1103/PhysRevLett.126.151801.
We study the impact of the mixing (LR mixing) between the standard model W boson and its hypothetical, heavier right-handed parter W_{R} on the neutrinoless double beta decay (0νββ decay) rate. Our study is done in the minimal left-right symmetric model assuming a type-II dominance scenario with charge conjugation as the left-right symmetry. We then show that the 0νββ decay rate may be dominated by the contribution proportional to this LR mixing, which at the hadronic level induces the leading-order contribution to the interaction between two pions and two charged leptons. The resulting long-range pion exchange contribution can significantly enhance the decay rate compared to previously considered short-range contributions. Finally, we find that even if future cosmological experiments rule out the inverted hierarchy for neutrino masses, there are still good prospects for a positive signal in the next generation of 0νββ decay experiments.
我们研究了标准模型W玻色子与其假设的较重右手伙伴WR之间的混合（LR混合）对无中微子双β衰变（0νββ衰变）率的影响。我们的研究是在最小左右对称模型中进行的，假设在电荷共轭作为左右对称的情况下为II型主导情景。然后我们表明，0νββ衰变率可能由与这种LR混合成正比的贡献主导，在强子层面上，这种混合对两个π介子和两个带电轻子之间的相互作用产生主导阶贡献。与之前考虑的短程贡献相比，由此产生的长程π介子交换贡献可以显著提高衰变率。最后，我们发现，即使未来的宇宙学实验排除了中微子质量的倒序层级，在下一代0νββ衰变实验中仍有获得正信号的良好前景。
