Observation of a hybrid spin resonance

A new type of spin depolarization resonance has been observed at the Brookh aven Alternating Gradient Synchroton (AGS). This spin resonance is identifi ed as a strong closed-orbit sideband around the dominant intrinsic spin res onance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical b etatron oscillation amplitude. This "hybrid" spin resonance cannot be overc ome by the partial snake at the AGS, but it can be corrected by the harmoni c orbit correctors.