We discuss the unique baryon number violation by two units neutron decay mode $n\to \overline{p}{e}^{+}\chi$, with χ being the standard model (SM) neutrino ν or antineutrino $\overline{\nu }$ or any beyond the SM light fermion, in the framework of effective field theory. This mode is kinematically allowed but rarely discussed theoretically or searched for experimentally. We estimate the lower bound on its partial lifetime from that of the dinucleon decay $np\to e^{+}\chi$ per oxygen nucleus ¹⁶O set by the Super-Kamiokande experiment, with a conservative bound ${\mathrm{\Gamma }}_{n\to \overline{p}{e}^{+}\chi }^{-1}>5.7\times {10}^{39}\mathrm{yrs}$. We also discuss its characteristic signature for the future experimental search and astrophysical implications.

我们讨论了两个单位中子衰减模式对重子数唯一的违反 $ñ\to \overline{p}{Ë}^{+}\chi$，其中χ是标准模型（SM）中微子ν或反中微子$\overline{\nu }$或在有效场论框架内的任何其他超出SM轻费米子的物体。在运动学上允许这种模式，但是很少在理论上讨论或通过实验进行搜索。我们根据二核子衰变估计其部分寿命的下限$ñp\to {Ë}^{+}\chi$Super-Kamiokande实验设定的每个氧核¹⁶ O的保守界限${\mathrm{\Gamma }}_{ñ\to \overline{p}{Ë}^{+}\chi }^{-\mathrm{1个}}>5.7\times {10}^{39}\mathrm{年}$。我们还将讨论其特征性标记，以供将来进行实验性搜索和天体物理学的启示。