Beam-beam simulations for LEP at 87 GeV

The result of beam-beam simulations for LEP at 87 GeV are reported. Three configurations are considered, with horizontal/vertical phase advances in the arcs of 90/60, 108/60 and 108/90 degrees. Two sets of errors - small and large - are used on the phase advances in the arcs, the b-functions at the collision points, the bunch populations, and the horizontal and vertical offsets at the collision points. Results are given for the ratio L/Lo of the observed luminosity and that achieved with the initial bunch populations and beam sizes. Regions in the fractional tune space (qx, qy) with smaller values of L/Lo are identified as resopnances, driven by the beam-beam collisions and the errors. For the 108/60 configuration and eight bunches in each beam, the predicted peak luminosities are L 5.4 E + 31 cm_2s-1 for a bunch current Ib = 0.44 mA and L 7.7 E + 31 cm-2s-1 for a bunch current Ib = 0,62 mA.