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 2.1 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. 
M.A. Leonova, J.A.Askari, K.N.Gordon, A.D.Krisch, J.Liu, V.S.Morozov,   D.A.Nees, R.S.Raymond, D.W.Sivers, V.K.Wong, F.Hinte...
physics.acc-ph hep-ex nucl-ex