DIRECT CP VIOLATION IN B-]X-S-GAMMA DECAYS AS A SIGNATURE OF NEW PHYSICS - ART. NO. 094012

We argue that the observation of a sizable direct CP asymmetry A(CP)(b -->s gamma) in the inclusive decays B --> X-s gamma would be a clean s ignal of new physics. In the standard model, A(CP)(b-->s gamma) can be calculated reliably and is found to be below 1% in magnitude. In exte nsions of the standard model with new CP-violating couplings, large CP asymmetries are possible without conflicting with the experimental va lue of the branching ratio for the decays B --> X-s gamma. In particul ar, large asymmetries arise naturally in models with enhanced chromoma gnetic dipole operators. Some generic examples of such models are expl ored and their implications for the semileptonic branching ratio and c harm yield in B decays discussed. [S0556-2821(98)07617-6]