Neutron–antineutron oscillations: Discrete symmetries and quark operators
Neutron–antineutron oscillations: Discrete symmetries and quark operators
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中子-反中子振荡：离散对称性和夸克算子
DOI：
10.1016/j.physletb.2018.11.014
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发表时间：
2018
影响因子：
4.4
通讯作者：
A. Vainshtein
中科院分区：
文献类型：
--
作者：
Z. Berezhiani;A. Vainshtein
我们分析了C、P和T离散对称性在中子-反中子跃迁中打破重子电荷B守恒的情况。在自由粒子的水平上，所有这些对称性都保持不变。这包括P反射，尽管通常认为中子和反中子具有相反的内部奇偶。这一解释可以追溯到1937年E. Majorana和G. Racah的论文，它基于宇称满足p2 = - 1的定义，而不是p2 = 1，并将P= i归因于中子和反中子。我们将此应用于| Δ B|= 2的六夸克算子的C， P和T分类。它允许指定对中子-反中子振荡有贡献的算符。剩余的操作者参与了其他| Δ B|= 2过程，特别是核不稳定性。我们还证明，只要转动不变性不被打破，外加磁场的存在不会诱发任何新的中子和反中子混合算子。
We analyze status of C, P and T discrete symmetries in application to neutron–antineutron transitions breaking conservation of baryon charge B by two units. At the level of free particles all these symmetries are preserved. This includes P reflection in spite of the opposite internal parities usually ascribed to neutron and antineutron. Explanation, which goes back to the 1937 papers by E. Majorana and by G. Racah, is based on a definition of parity satisfying P 2=− 1, instead of P 2= 1, and ascribing P= i to both, neutron and antineutron. We apply this to C, P and T classification of six-quark operators with| Δ B|= 2. It allows to specify operators contributing to neutron–antineutron oscillations. Remaining operators contribute to other| Δ B|= 2 processes and, in particular, to nuclei instability. We also show that presence of external magnetic field does not induce any new operator mixing the neutron and antineutron provided that rotational invariance is not broken.