Using 180 pb-1 of data collected with the CDF II detector at
the Tevatron, we measure the first two moments of the hadronic invariant
mass-squared distribution in charmed semileptonic B decays. From these we
determine the non-perturbative Heavy Quark Effective Theory parameters
Lambda and gamma_1 used to relate the B meson semileptonic branching ratio
to the CKM matrix element |V_cb|. For a minimum lepton momentum of 0.7
GeV/c in the B rest frame we measure the first two moments of the D** -->
D(*) pi component to be (m2_(D**) = (5.83 +/- 0.16_stat +/- 0.08_syst)
GeV2/c4 and <(m2_(D**) - <m2_(D**>)2> = (1.30 +/- 0.69_stat +/-
0.22_syst) GeV4/c8. Combining these with the discrete mass terms from the
D and D* mesons, we find the total moments to be <M2_(chi(c))> - m-bar2_D
= (0.467 +/- 0.038_stat +/- 0.068_syst) GeV2/c4 and <(M2_(chi(c)) -
<M2_(chi(c)>)2> = (1.05 +/- 0.26_stat +/- 0.13_syst) GeV4/c8, where
m-bar_D is the spin-averaged D mass. The systematic error is dominated by
the uncertainties in the world-average branching ratios used to combine the
D, D*, and D** contributions. The analysis makes no assumptions about the
shape or resonant structure of the D** --> D(*) pi invariant mass
distribution.
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Updated: Wednesday, 2005 March 23 14:46:30 CST automatically from input from Carol Picciolo