Assessing the Merits of Positron Polarization at a Linear Collider

The possibility of polarized positron beams at a future linear collider has created much interest. At the 2001 Snowmass meeting, a study group (designated E3) included a subgroup whose charge was to closely examine the merits, as quantitatively as possible, of this option. The leading issues are outlined here, and a few physics examples are given. The deciding issues are, however, likely to be technological, as positron polarization would to be a very complex and expensive addition to the accelerator.