Spin Depolarization due to Beam-Beam Interaction in NLC

Calculations of spin depolarization e ects due to the beam-beam interaction are presented for several NLC designs. The depolarization comes from both classical (Bargmann-Michel-Telegdi precession) and quantum (Sokolov-Ternov spinip) e ects. It is anticipated that some physics experiments at future colliders will require a knowledge of the polarization to better than 0.5% precision. We compare the results of CAIN simulations with the analytic estimates of Yokoya and Chen for head-on collisions. We also study the e ects of transverse o sets and beamstrahlung-induced energy spread. y K.Yokoya and P.Chen, 8th International Conference on High Energy Spin Physics, Minneapolis, 12-17 September 1988. Presented at Advanced ICFA Beam Dynamics Workshop on Quantum Aspects of Beam Physics, Capri, Italy, October 10-15, 2000 Work supported by Department of Energy contract DE{AC03{76SF00515. SPIN DEPOLARIZATION DUE TO BEAM-BEAM INTERACTION IN NLC KATHLEEN A. THOMPSON Stanford Linear Accelerator Center Stanford University, Stanford, CA 94309 E-mail: kthom@SLAC.Stanford.edu Calculations of spin depolarization e ects due to the beam-beam interaction are presented for several NLC designs. The depolarization comes from both classical (Bargmann-Michel-Telegdi precession) and quantum (Sokolov-Ternov spinip) e ects. It is anticipated that some physics experiments at future colliders will require a knowledge of the polarization to better than 0.5% precision. We compare the results of CAIN simulations with the analytic estimates of Yokoya and Chen for head-on collisions. We also study the e ects of transverse o sets and beamstrahlung-induced energy spread.