LEADING LOGARITHMS OF THE B-QUARK MASS IN INCLUSIVE B-]X(S)GAMMA-DECAY

Part of the order alpha(s) correction to the inclusive B --> X(s) gamm a photon spectrum is enhanced by log(m(b)(2)/m(s)(2)). We discuss its origin and sum the corrections proportional to [alpha(s) log(m(b)(2)/m u(2))](n) to all orders. These are the calculable leading logarithms i n the parton fragmentation functions of a quark or gluon into a photon . Although the gluon fragmentation into a photon starts only at order alpha(s)(2), its contribution is of the same order as the s quark's in the leading log sum. For not too small values of the photon energy, t he resummation yields a moderate suppression. In the standard model, t he coefficient of the operator whose matrix element gives rise to such terms is small. A measurement of the photon spectrum around 1 GeV wou ld provide a theoretically clean determination of C-8, the Wilson coef ficient of the b --> s g operator.