Higher order Spin resonances in a 2.1-GeV/c polarized proton beam

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