Observations of the beam-beam interaction in Hadron colliders

The beam-beam issues in three hadron colliders were reviewed. The beam-beam interaction was not a major problem in the ISR since it collided unbunched beams. The performance of bunced beam colliders, however, was seriously limited by the beam-beam interaction. Observations at the CERN SPS showed that the beam-beam interaction excites resonances up to order 16. The SPS experiments demonstrated the “self-scraping” phenomenon which was reproduced in the TEVATRON later. Other beam-beam experiments in the SPS showed the detrimental effects of having different emittances for protons and antiprotons, and the excitation of the 13th-order resonance in the case of separated beams.