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Phys. Rev. D 71, 051103 (2005) [9 pages]

Measurement of the moments of the hadronic invariant mass distribution in semileptonic B decays

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D. Acosta et al. CDF Collaboration
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Rapid Communication Received 1 February 2005; published 18 March 2005

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 nonperturbative Heavy Quark Effective Theory parameters Λ and λ1 used to relate the B meson semileptonic branching ratio to the CKM matrix element |Vcb|. 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(*)π component to be ⟨mD**2⟩=(5.83±0.16stat±0.08syst)  GeV2/c4 and ⟨(mD**2-⟨mD**2⟩)2⟩=(1.30±0.69stat±0.22syst)  GeV4/c8. Combining these with the discrete mass terms from the D and D* mesons, we find the total moments to be ⟨MXc2⟩-m̅ D2=(0.467±0.038stat±0.068syst)  GeV2/c4 and ⟨(MXc2-⟨MXc2⟩)2⟩=(1.05±0.26stat±0.13syst)  GeV4/c8, where m̅ 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(*)π invariant mass distribution.


©2005 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevD.71.051103
DOI: 10.1103/PhysRevD.71.051103
PACS: 13.20.He, 12.15.Hh, 12.39.Hg

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