Observation of $\overline{B}\to D^{(\ast )}{\pi }^{+}{\pi }^{-}{\ell }^{-}\overline{\nu }$ decays in $e^{+}{e}^{-}$ collisions at the ${\rm Y}(4S)$ resonance

Abstract

We report on measurements of the decays of $\overline{B}$ mesons into the semileptonic final states $\overline{B}\to D^{(\ast )}{\pi }^{+}{\pi }^{-}{\ell }^{-}\overline{\nu }$, where $D^{(\ast )}$ represents a $D$ or $D^{\ast }$ meson and ${\ell }^{-}$ is an electron or a muon. These measurements are based on $471\times 10^6$ $B\overline{B}$ pairs recorded with the $BABAR$ detector at the SLAC asymmetric $B$ Factory PEP-II. We determine the branching fraction ratios $R_{{\pi }^{+}{\pi }^{-}}^{(\ast )}=\mathcal{B}(\overline{B}\to D^{(\ast )}{\pi }^{+}{\pi }^{-}{\ell }^{-}\overline{\nu })/\mathcal{B}(\overline{B}\to D^{(\ast )}{\ell }^{-}\overline{\nu })$ using events in which the second $B$ meson is fully reconstructed. We find $R_{{\pi }^{+}{\pi }^{-}}=0.067\pm 0.010\pm 0.008$ and $R_{{\pi }^{+}{\pi }^{-}}^{\ast }=0.019\pm 0.005\pm 0.004$, where the first uncertainty is statistical and the second is systematic. Based on these results, we estimate that $\overline{B}\to D^{(\ast )}\pi \pi {\ell }^{-}\overline{\nu }$ decays, where $\pi$ denotes both a ${\pi }^{\pm }$ and ${\pi }^0$ meson, account for up to half the difference between the measured inclusive semileptonic branching fraction to charm hadrons and the corresponding sum of previously measured exclusive branching fractions.

arXiv comment8 pages, 2 figures, submitted to PRL

References in corpus (11)

• The BABAR Detector
• The Precision Monte Carlo Event Generator KK For Two-Fermion Final States In e+e- Collisions
• Evidence for an excess of B -> D(*) Tau Nu decays
• Measurement of an Excess of B -> D(*) Tau Nu Decays and Implications for Charged Higgs Bosons
• Measurement of the branching ratio of $\bar{B}\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to $\bar{B}\to D^{(\ast )}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with hadronic tagging at Belle
• Measurement of the ratio of branching fractions $\mathcal{B}({\overline{B}}^0\to D^{\ast +}{\tau }^{-}{\overline{\nu }}_{\tau })/\mathcal{B}({\overline{B}}^0\to D^{\ast +}{\mu }^{-}{\overline{\nu }}_{\mu })$
• Kernel Estimation in High-Energy Physics
• Current status of the Standard Model CKM fit and constraints on $\Delta F=2$ New Physics
• Observation of B^0 \to D^{*-} τ^+ ν_τ decay at Belle
• Observation of B+ -> Dbar*0 tau+ nu_tau and Evidence for B+ -> Dbar^0 tau+ nu_tau at Belle
• A proposal to solve some puzzles in semileptonic B decays

Cited by in corpus (12)

• Semileptonic form factors for $B\to D^{\ast }\ell \nu$ at nonzero recoil from 2 + 1-flavor lattice QCD
• Semileptonic $B_{(s)}$ decays to excited charmed mesons with $e,\mu ,\tau$ and searching for new physics with $R(D^{\ast \ast })$
• Extraction of form Factors from a Four-Dimensional Angular Analysis of $\overline{B}\to D^{\ast }{\ell }^{-}{\overline{\nu }}_{\ell }$
• Measurements of Partial Branching Fractions of Inclusive $B\to X_u{\ell }^{+}{\nu }_{\ell }$ Decays with Hadronic Tagging
• Measurement of the inclusive electron spectrum from B meson decays and determination of |Vub|
• A test of light-lepton universality in the rates of inclusive semileptonic $B$-meson decays at Belle II
• First Measurement of $R(X_{\tau /\ell })$ as an Inclusive Test of the $b\to c\tau \nu$ Anomaly
• First observation of $B\to {\bar{D}}_1(\to \bar{D}{\pi }^{+}{\pi }^{-}){\ell }^{+}{\nu }_{\ell }$ and measurement of the $B\to {\bar{D}}^{(\ast )}\pi {\ell }^{+}{\nu }_{\ell }$ and $B\to {\bar{D}}^{(\ast )}{\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ branching fractions with hadronic tagging at Belle
• Measurement of the branching fraction of $B\to D^{(\ast )}\pi \ell \nu$ at Belle using hadronic tagging in fully reconstructed events
• Angular analyses of exclusive $\overline{B}\to X_J{\ell }_1{\ell }_2$ decays for spin $J\le 4$
• An experimentalist's guide to the semileptonic bottom to charm branching fractions
• Measurement of the Ratio of Partial Branching Fractions of Inclusive $\overline{B}\to X_u\ell \overline{\nu }$ to $\overline{B}\to X_c\ell \overline{\nu }$ and the Ratio of their Spectra with Hadronic Tagging