Perturbative QCD- and power-corrected hadron spectra and spectral moments in the decay B #->#X_sl"+l"-

We compute the leading order (in #alpha#_s perturbative QCD and power (1/m"2_b) corrections) to the hadronic invariant mass and hadron energy spectra in the decay B#->#X_sl"+l"- in standard model. The computations are carried out using the heavy quark expansion technique (HQET) and a perturbative-QCD improved Fermi motion (FM) model which takes into account B-meson wave-function effects. The corrections in the hadron energy (E_H) spectrum are found to be small over a good part of this spectrum in both methods. However, the expansion in 1/m_b in HQET fails near the lower kinematic end-point and at the c anti c threshold. The hadronic invariant mass (S_H) spectrum is calculable only over a limited range S_H> anti #LAMBDA#m_B in the heavy quark expansion, where anti #LAMBDA##approx =#m_B-m_b. We also present results for the first two hadronic moments left angle S"n_H right angle and left angle E"n_H right angle, n=1,2, working out their sensitivity on the HQET and FM model parameters. For equivalent values of these parameters, the moments in these methods are remarkably close to each others. The constraints following from assumed values left angle S_H"n right angle on the HQET parameters #lambda#_1 and anti #LAMBDA# are worked out. Data from forthcoming B facilities could be used to measure the short-distance contribution in B#->#X_sl"+l"- and constrain the HQET parameters #lambda#_1 and anti #LAMBDA#. This could be combined with complementary constraints from the decay B#->#Xl#nu#_l to determine these parameters precisely. We also study the effect of the experimental cuts, used recently by the CLEO collaboration in searching for the decay B#->#X_sl"+l"-, on the branching ratios, hadron spectra and hadronic invariant mass moments using the FM model. (orig.)Available from TIB Hannover: RA 2999(98-030) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman