Study of incoherent pair generation in the beam-beam interaction simulation program Guinea-Pig

Abstract

Talk given at 2005 ALCPG & ILC Workshops - Snowmass, U.S.A., Aug. 14-27, 2005. Pulbished in the proceedings : www.slac.stanford.edu/econf/C0508141/proc/papers/ALCPG0933.PDFInternational audienceThis paper deals with two topics: the generation of incoherent pairs in two-beam-beam simulation programs, Guinea-Pig and CAIN, and the influence of the ILC beam parameter choices on the background in the micro-vertex detector (VD) induced by direct hits. One of the processes involved in incoherent pair creation (IPC) is equivalent to a four fermions interaction and its cross section can be calculated exactly with a dedicaded generator, BDK. A comparison of Guinea-Pig and CAIN results with BDK allows to identify and quantify the uncertainties on IPC background predictoins and to benchmark the Guinea-Pig calculation. Based on this simulation and different VD designs, the five currently suggested ILC beam parameter sets have been compared regarding IPC background induced in the VD by direct IPC hits. We emphasize that the high luminosity set, as it is currently defined, would constrain both the choices of magnetic field and VD inner layer radius