Is the $\sigma (600)$ a Glueball? Two photon reactions can tell us

Abstract

Minkowski and Ochs have recently argued that the small two photon coupling of a conjectured $\sigma (600)$ is so small that it is likely to be a glueball. We ask whether this can be so or whether it is simply gauge invariance that produces the observed low mass suppression?

Comments: 7 pages, 6 figures Talk given at the 13th International Workshop on Photon-Photon Collisions (Photon2000), September 2000, Ambleside, U.K. --- to appear in the Proceedings