The (B)over-bar -> X-s gamma photon spectrum - art. no. 034019.

The photon energy spectrum in inclusive weak radiative (B) over bar --> X(s )gamma decay is computed to order alpha(s)(2)beta(0). This result is used t o extract a value for the heavy quark effective theory (HQET) parameter <(L ambda)over bar> from the average [1-2E(gamma)/m(B)], and a value of the par ameter lambda(1) from [(1-2E(gamma)/m(B))(2)]. An accurate measurement of [ 1-2E(gamma)/m(B)] can determine the size of the nonperturbative contributio ns to the Y(1S) mass which cannot be absorbed into the b quark pole mass. [ S0556-2821(99)00217-9].