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 λ 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 (*)π component to be 〈m D**2〉 = (5.83 ± 0.16 stat ± 0.08 syst) GeV 2/c 4 and 〈(m D**2 - 〈m D**2〉) 2〉 = (1.30 ± 0.69 stat ± 0.22 syst) GeV 4/c 8. Combining these with the discrete mass terms from the D and D* mesons, we find the total moments to be 〈M Ξc2〉 - m̄ D2 = (0.467 ± 0.038 stat ± 0.068 syst GeV 2/c 4 and 〈(M Ξc2 - 〈M Ξc2〉) 2〉 = (1.05 ± 0.26 stat ± 0.13 syst) GeV 4/c 8, where m̄ 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.

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

Piacentino G.;
2005-01-01

Abstract

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 λ 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 (*)π component to be 〈m D**2〉 = (5.83 ± 0.16 stat ± 0.08 syst) GeV 2/c 4 and 〈(m D**2 - 〈m D**2〉) 2〉 = (1.30 ± 0.69 stat ± 0.22 syst) GeV 4/c 8. Combining these with the discrete mass terms from the D and D* mesons, we find the total moments to be 〈M Ξc2〉 - m̄ D2 = (0.467 ± 0.038 stat ± 0.068 syst GeV 2/c 4 and 〈(M Ξc2 - 〈M Ξc2〉) 2〉 = (1.05 ± 0.26 stat ± 0.13 syst) GeV 4/c 8, where m̄ 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.
http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PRVDAQ000071000005051103000001&idtype=cvips
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11695/88076
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