Coherent beam-beam interaction limit in asymmetric ring colliders

Abstract

We study the effect of the beam-beam interaction on the coherent dipole oscillations of rigid bunches circulating in asymmetric e +e − (two-ring) colliders, with circumference ratio ifK +/K −, where K + bunches of the e + beam collide with K − bunches of the e − beam. Unstable regions appear densely in the tune diagram, when one or both of K + and K − are large. This effect poses a severe restriction on the choice of K + and K −.