Angular momentum effects in neutron decay

TL;DR

This paper explores how structured neutron states with orbital angular momentum influence beta decay, revealing that emitted particles' angular distributions can reveal the neutron's wave packet structure and symmetries.

Contribution

It introduces a detailed analysis of neutron beta decay involving non-plane-wave states with orbital angular momentum, highlighting their effects on emission distributions and potential for quantum material studies.

Findings

Proton spectral-angular distributions are highly sensitive to neutron wave packet structure.

Angular distributions of emitted particles reflect the spatial symmetries of neutron states.

Structured neutron states can be characterized through decay product measurements.

Abstract

We investigate the intriguing phenomenon of beta decay of a free neutron in a non-plane-wave(structured) state. Our analysis covers three types of states: unpolarized vortex (Bessel) neutrons that possess nonzero orbital angular momentum (OAM), Laguerre-Gaussian wave packets, and spin-correlated OAM (spin-orbit) states characterized by unique polarization patterns. These states are of particular interest as they have recently been generated in neutron optics experiments and have promising applications in studies of quantum magnetic materials. The spectral-angular distributions (SAD) of the emitted electrons and protons are examined. We show that the high sensitivity of the protons SAD to the structure of the neutron wave packet can be used as a tool to extract the distinctive features of the non-plane-wave neutron states. Furthermore, we demonstrate that the angular distribution of the emitted particles serves as a reflection of the spatial symmetries inherent to the neutron wave packet.