DEPOLARIZATION AND LUMINOSITY ISSUES IN A HIGH ENERGY LINEAR COLLIDER

Abstract

In the next energy frontier of an electron–positron (electron–electron) linear collider its demand of both extreme high energy and high luminosity leads to a high production of W+W- (W- particles). In order to delineate processes of interest, it is advantageous to polarize the electron and positron beams, as this tends to suppress the above known processes and thus heightens the sensitivity to the sought-after processes. We investigate the possible depolarization of the electron (positron) beams in the acceleration stages as well as in the collision point. We take the example of the laser wakefield accelerator design at 5 TeV center of mass energy of colliding beams. We find that in this design the spin depolarization due to the stage jitter noise is certainly negligible, and the depolarization due to the self-generated fields at the collision point is still tolerable. We also consider several lower energy scenarios as they might be possible to achieve in a single beam driven acceleration stage.