Spin resonance crossing in the Relativistic Heavy Ion Collider (RHIC)

In a high energy accelerator the polarization distribution of the beam can vary substantially across the beam. This decreases the amount of beam polarization provided to experiments. A method has been developed to calculate the beam polarization distribution based on adiabatic particle and spin excitation by inducing coherent betatron oscillations using an ac dipole. In earlier studies we calculated the beam polarization distribution in Brookhaven´s Relativistic Heavy Ion Collider (RHIC) at fixed energy to compare spin motion on and away from strong spin resonances. In this paper we present calculations of the beam polarization distribution during spin resonance crossing in the RHIC. Furthermore beam polarization losses during spin resonance crossing for different vertical beam emittances have been studied