Measurement of the Partial Branching Fraction for Inclusive Charmless Semileptonic B Decays and Extraction of $|V_{ub}|$

Abstract

Charmless semileptonic decays, $\bar{B}\to X_u\ell \bar{\nu }$, are studied in a sample of 232 million $B\bar{B}$ decays recorded with the BaBar detector, in events where the decay of the second $B$ meson is fully reconstructed. Inclusive charmless decays are selected in kinematic regions where the dominant background from semileptonic B decays to charm is reduced by requirements on the hadronic mass $M_X$ and the momentum transfer $q^2$. The partial branching fraction for $\bar{B}\to X_u\ell \bar{\nu }$ decays for $M_X<1.7$ GeV/c^2 and $q^2>8$ Gev^2/c^4 is measured to be $\Delta \mathcal{B}(\bar{B}\to X_u\ell \bar{\nu })=(0.87\pm 0.09_{\mathrm{stat}}\pm 0.09_{\mathrm{sys}}\pm 0.01_{\mathrm{th}})\times 10^{-3}$. The CKM matrix element $|V_{ub}|$ is determined by using theoretical calculations of phase space acceptances. Theoretical uncertainties in this extrapolation are reduced by using the inclusive $b\to s\gamma$ photon spectrum and moments of the $b\to c\ell \bar{\nu }$ lepton energy and hadronic invariant mass.

19 pages, 2 figures, submitted to the XXII International Symposium on Lepton-Photon Interactions at High Energy, 30 June - 5 July, Uppsala, Sweden

References in corpus (3)

• Theory of Charmless Inclusive B Decays and the Extraction of V_{ub}
• The CKM Matrix and the Unitarity Triangle
• Extraction of the b-quark shape function parameters using the Belle B->X_s gamma photon energy spectrum

Cited by in corpus (2)

• Inclusive semileptonic B decays and the determination of |V_ub|
• Determination of |Vub|