Higher Order Spin Resonances in a 2.1 GeV/c Polarized Proton Beam

TL;DR

This study investigates higher order spin resonances in a 2.1 GeV/c polarized proton beam, revealing complex behaviors of depolarization and spin-flip effects that challenge prior assumptions about resonance strength hierarchy.

Contribution

It provides the first detailed experimental comparison of first and higher order spin resonances in a polarized proton beam at this energy.

Findings

First order vertical resonance causes full spin-flip.

Higher order resonances cause partial depolarization.

Data contradicts the assumption that lower order resonances are always stronger.

Abstract

Spin resonances can depolarize or spin-flip a polarized beam. We studied 1st and higher order spin resonances with stored 2.1 GeV/c vertically polarized protons. The 1st order vertical ({\nu}y) resonance caused almost full spin-flip, while some higher order {\nu}y resonances caused partial depolarization. The 1st order horizontal ({\nu}x) resonance caused almost full depolarization, while some higher order {\nu}x resonances again caused partial depolarization. Moreover, a 2nd order {\nu}x resonance is about as strong as some 3rd order {\nu}x resonances, while some 3rd order {\nu}y resonances are much stronger than a 2nd order {\nu}y resonance. One thought that {\nu}y spin resonances are far stronger than {\nu}x, and that lower order resonances are stronger than higher order; the data do not support this.