Measurement of the Hadronic Mass Spectrum in B to Xulnu Decaysand Determination of the b-Quark Mass at the BaBar Experiment

Abstract

I present preliminary results of the measurement of the hadronic mass spectrum and its first three spectral moments in inclusive charmless semileptonic B-meson decays. The truncated hadronic mass moments are used for the first determination of the b-quark mass and the nonperturbative parameters {mu}{sub {pi}}{sup 2} and {rho}{sub D}{sup 3} in this B-meson decay channel. The study is based on 383 x 10{sup 6} B{bar B} decays collected with the BABAR experiment at the PEP-II e{sup +}e{sup -} storage rings, located at the Stanford Linear Accelerator Center. The first, second central, and third central hadronic mass moment with a cut on the hadronic mass m{sub X}{sup 2} 1 GeV are measured to be: M{sub 1} = (1.96 {+-} 0.34{sub stat} {+-} 0.53{sub syst}) GeV{sup 2}; U{sub 2} = (1.92 {+-} 0.59{sub stat} {+-} 0.87{sub syst}) GeV{sup 4}; and U{sub 3} = (1.79 {+-} 0.62{sub stat} {+-} 0.78{sub syst}) GeV{sup 6}; with correlation coefficients {rho}{sub 12} = 0.99, {rho}{sub 23} = 0.94, and {rho}{sub 13} = 0.88, respectively. Using Heavy Quark Effective Theory-based predictions in the kinetic scheme we extract: m{sub b} = (4.60 {+-} 0.13{sub stat} {+-} 0.19{sub syst} {+-} 0.10{sub theo} GeV); {mu}{sub {pi}}{sup 2} = (0.40 {+-} 0.14{sub stat} {+-} 0.20{sub syst} {+-} 0.04{sub theo}) GeV{sup 2}; {rho}{sub D}{sup 3} = (0.10 {+-} 0.02{sub stat} {+-} 0.02{sub syst} {+-} 0.07{sub theo}) GeV{sup 3}; at {mu} = 1 GeV, with correlation coefficients {rho}{sub m{sub b}{mu}{sub {pi}}{sup 2}} = -0.99, {rho}{sub {mu}{sub {pi}}{sup 2}{rho}{sub D}{sup 3}} = 0.57, and {rho}{sub m{sub b}{rho}{sub D}{sup 3}} = -0.59. The results are in good agreement with earlier determinations in inclusive charmed semileptonic and radiative penguin B-meson decays and have a similar accuracy. Through the comparison of this result to those obtained in other channels, this provides a test of the Heavy Quark Effective Theory predictions that are used for the determination of |V{sub ub}|. In addition, the measured dependence of the hadronic mass moments on the hadronic mass cut is compared to the dependence predicted by Heavy Quark Effective Theory.