Measurement of the inclusive electron spectrum from B meson decays and determination of |Vub|

Abstract

Based on the full BaBar data sample of 466.5 million BBbar pairs, we present measurements of the electron spectrum from semileptonic B meson decays. We fit the inclusive electron spectrum to distinguish Cabibbo-Kobayashi-Maskawa (CKM) suppressed B -> Xu e nu decays from the CKM-favored B -> Xc e nu decays, and from various other backgrounds, and determine the total semileptonic branching fraction BR(B -> X e nu) = (10.34 +- 0.04_stat +- 0.26_syst)%, averaged over B+- and B0 mesons. We determine the spectrum and branching fraction for charmless B -> Xu e nu decays and extract the CKM element |Vub|, by relying on four different QCD calculations based on the heavy quark expansion. While experimentally, the electron momentum region above 2.1GeV/c is favored, because the background is relatively low, the uncertainties for the theoretical predictions are largest in the region near the kinematic endpoint. Detailed studies to assess the impact of these four predictions on the measurements of the electron spectrum, the branching fraction, and the extraction of the CKM matrix element |Vub| are presented, with the lower limit on the electron momentum varied from 0.8GeV/c to the kinematic endpoint. We determine |Vub| using each of these different calculations and find, |Vub| = (3.794 +- 0.107_exp +0.292-0.219_SF +0.078-0.068_theory)*10^{-3} (De Fazio and Neubert), (4.563 +- 0.126_exp +0.230-0.208_SF +0.162-0.163_theory)*10^{-3} (Bosh, Lange, Neubert, and Paz), (3.959 +- 0.104_exp +0.164-0.154_SF +0.042-0.079_theory)*10^{-3} (Gambino, Giordano, Ossola, and Uraltsev), (3.848 +- 0.108_exp +0.084-0.070_theory)*10^{-3} (dressed gluon exponentiation), where the stated uncertainties refer to the experimental uncertainties of the partial branching fraction measurement, the shape function parameters, and the theoretical calculations.

arXiv comment27 pages, 42 postscript figures, Published in Phys. Rev. D95, 072001 (2017)

References in corpus (47)

• The BABAR Detector
• Semileptonic Meson Decays in the Quark Model: An Update
• Inclusive Semileptonic B and Polarized Lambda_b Decays from QCD
• Dispersive Bounds on the Shape of B -> D^(*) l nu Form Factors
• Differential Distributions in Semileptonic Decays of the Heavy Flavors in QCD
• On the Motion of Heavy Quarks inside Hadrons: Universal Distributions and Inclusive Decays
• QCD Anatomy of B -> X_s gamma Decays
• Aspects Of Heavy Quark Theory
• Analysis of the Photon Spectrum in Inclusive $B\to X_s\gamma$ Decays
• Factorization and Shape-Function Effects in Inclusive B-Meson Decays
• QCD-Based Interpretation of the Lepton Spectrum in Inclusive $\bar{B}\to X_u\ell \bar{\nu }$ Decays
• B decay and the Upsilon mass
• Determination of the quark coupling strength $|V_{ub}|$ using baryonic decays
• B decays in the upsilon expansion
• Semileptonic B decays to excited charmed mesons
• Observation of new resonances decaying to $D\pi$ and $D^{\ast }\pi$ in inclusive $e^{+}{e}^{-}$ collisions near $\sqrt{s}=$10.58 GeV
• Renormalization-Group Improved Calculation of the B->Xs+gamma Branching Ratio
• B -> X_u l nu decay distributions to order alpha_s
• Shape function effects in B -> X_s gamma and B -> X_u l nu decays
• Inclusive semileptonic B decays and the determination of |V_ub|
• Inclusive spectra in charmless semileptonic B decays by Dressed Gluon Exponentiation
• Measurements of the B -> X_s gamma Branching Fraction and Photon Spectrum from a Sum of Exclusive Final States
• Subleading Shape Functions in Inclusive B Decays
• Study of $D_J$ meson decays to $D^{+}{\pi }^{-}$, $D^0{\pi }^{+}$ and $D^{\ast +}{\pi }^{-}$ final states in pp collision
• The second order QCD contribution to the semileptonic b -> u decay rate
• Improved Measurement of |V_ub| with Inclusive Semileptonic B Decays
• Soft Pion Emission in Semileptonic $B$-Meson Decays
• Measurement of the Inclusive Electron Spectrum in Charmless Semileptonic B Decays Near the Kinematic Endpoint and Determination of |Vub|
• B semileptonic moments at NNLO
• A proposal to solve some puzzles in semileptonic B decays
• Measurement of |V_ub| near the endpoint of the electron momentum spectrum from semileptonic B-meson decays
• Two-Loop Relations for Heavy-Quark Parameters in the Shape-Function Scheme
• Theoretical Uncertainties in Gamma_sl(b->u)
• Measurements of the Branching fractions for $B_{(}s)->D_{(}s)\pi \pi \pi$ and ${\Lambda }_b^0->{\Lambda }_c^{+}\pi \pi \pi$
• Do Higher Order Perturbative Corrections Upset |V_{cb}| and |V_{ub}| Determined from Semileptonic Widths?
• Radiative B decay spectrum: DGE at NNLO
• Heavy quark symmetry in B -> D(*) ell nu spectra
• Observation of the D1(2420)->DPI+PI- decays
• Determination of |Vub|/|Vcb| with DELPHI at LEP
• Observation of $\overline{B}\to D^{(\ast )}{\pi }^{+}{\pi }^{-}{\ell }^{-}\overline{\nu }$ decays in $e^{+}{e}^{-}$ collisions at the ${\rm Y}(4S)$ resonance
• Study of Inclusive B- and Bbar0 Decays to Flavor-Tagged D, D_s and Lambda_c
• Measurement of Vub using b hadron semileptonic decays
• Impact of Four-Quark Shape Functions on Inclusive B Decay Spectra
• NNLO corrections to B --> X_u l nu and the determination of |V_ub|
• Determination of V_ub from semileptonic B decays
• Inclusive distributions near kinematic thresholds
• Memo on Extracting |V(cb)| and |V(ub)/V(cb)| from semileptonic B decays

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