Jach Terrence, Vinson John
Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.
Phys Rev C. 2022 Jun;105(6). doi: 10.1103/PhysRevC.105.L061601.
A standard method to detect thermal neutrons is the nuclear interaction He(n,p)H. The spin dependence of this interaction is also the basis of a neutron spin-polarization filter using nuclear polarized He. We consider the corresponding interaction for neutrons placed in an intrinsic orbital angular momentum (OAM) state. We derive the relative polarization-dependent absorption cross sections for neutrons in an OAM state. The absorption of those neutrons results in compound states , , and . Varying the three available polarizations tests that an OAM neutron has been absorbed and probes which decay states are physically possible. We describe the energetically likely excited states of He after absorption, taking account of the odd parity of the compound state. This provides a definitive method for detecting neutron OAM states and suggests that intrinsic OAM states offer the possibility to observe new physics, including anomalous cross sections and new channels of radioactive decay.
检测热中子的标准方法是核相互作用He(n,p)H。这种相互作用的自旋依赖性也是使用核极化氦的中子自旋极化滤波器的基础。我们考虑了处于内禀轨道角动量（OAM）态的中子的相应相互作用。我们推导了处于OAM态的中子的相对极化相关吸收截面。这些中子的吸收会产生复合态 、 和 。改变三种可用极化来测试OAM中子是否已被吸收，并探测哪些衰变态在物理上是可能的。我们考虑到复合态的奇宇称，描述了吸收后氦的能量上可能的激发态。这提供了一种检测中子OAM态的明确方法，并表明内禀OAM态提供了观察新物理现象的可能性，包括反常截面和新的放射性衰变通道。
