  We resum to next-to-leading order the distribution in the ratio of the
invariant hadron mass mX to the total hadron energy EX and the distribution in
mX in the semileptonic decays B -> Xu l nu. By expanding our formulas, we
obtain the coefficients of all the infrared logarithms at O(alphaS^2) and of
the leading ones at O(alphaS^3). We explicitly show that the relation between
these semileptonic spectra and the photon spectrum in the radiative decay B ->
Xs gamma is not a purely short-distance one. There are long-distance effects in
the semileptonic spectra which are not completely factorized by the structure
function as measured in the radiative decay and have to be modelled in some
way.
