Spin rotation of the planar channeled antiproton in bent crystal

TL;DR

This paper derives an exact solution for the spin rotation of relativistic antiprotons in bent crystals, showing that polarization oscillates but effectively aligns with the crystal bending angle due to beam divergence effects.

Contribution

It provides the first exact analytical solution of the BMT equation for spin dynamics in bent crystal channeling, accounting for realistic beam divergence.

Findings

Polarization oscillates during crystal passage

Spin rotation aligns with crystal bending angle

Beam divergence causes rapid damping of oscillations

Abstract

In the present paper, we derive the exact solution of the BMT equation for the spin rotation of relativistic negatively charged particles passing through a thin bent crystal in the regime of planar channeling. It is shown that during the passage through the crystal a particle polarization vector oscillates. If one takes into account, the energy and angular divergence of the initial particle beam these oscillations die fast with particle penetration length into a crystal, and particle spin rotation is determined by the crystal bending angle.