Satellite Resonances Due to Beam-Beam Interaction

Experimental and theoretical investigations have shown that the luminosity of the storage ring DORIS is limited by betatron-synchrotron resonances which are produced by the beam-beam interaction. The resonance frequencies are given by Q??a=(p+rQs)/q, where p, q, r are integers and Q?? and Qs are the betatron and synchrotron wave numbers, respectively. It is proved that these resonances are caused by the crossing angle. Analytical investigations as well as computer simultionsare in good agreement with measurements made at DORIS. The analytical investigation further shows that also a dispersion at the interaction point will produce these satellite resonances.