Measurement of the Branching Fraction of the Decay ${\mathbf{B}}^{+}\to {\mathbf{\pi }}^{+}{\mathbf{\pi }}^{-}{\mathbf{\ell }}^{+}{\mathbf{\nu }}_{\mathbf{\ell }}$ in Fully Reconstructed Events at Belle

Abstract

We present an analysis of the exclusive $B^{+}\to {\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ decay, where $\ell$ represents an electron or a muon, with the assumption of charge-conjugation symmetry and lepton universality. The analysis uses the full ${\rm Y}(4S)$ data sample collected by the Belle detector, corresponding to 711 fb${}^{-1}$ of integrated luminosity. We select the events by fully reconstructing one $B$ meson in hadronic decay modes, subsequently determining the properties of the other $B$ meson. We extract the signal yields using a binned maximum-likelihood fit to the missing-mass squared distribution in bins of the invariant mass of the two pions or the momentum transfer squared. We measure a total branching fraction of $\mathcal{B}(B^{+}\to {\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell })=[22.7_{-1.6}^{+1.9}(\mathrm{stat})\pm 3.5(\mathrm{syst})]\times 10^{-5}$, where the uncertainties are statistical and systematic, respectively. This result is the first reported measurement of this decay.

arXiv comment23 pages, 19 figures

References in corpus (31)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• CP Violation and the CKM Matrix: Assessing the Impact of the Asymmetric B Factories
• New Results on B->pi, K, eta Decay Formfactors from Light-Cone Sum Rules
• The Belle II Physics Book
• Semileptonic Meson Decays in the Quark Model: An Update
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2018
• Dispersive Bounds on the Shape of B -> D^(*) l nu Form Factors
• Exclusive Semileptonic and Rare B-Meson Decays in QCD
• Model-independent description of $B\to \pi l\nu$ decays and a determination of $|V_{ub}|$
• The Unitarity Triangle Fit in the Standard Model and Hadronic Parameters from Lattice QCD: A Reappraisal after the Measurements of Delta m_s and BR(B to tau nu)
• Determination of the quark coupling strength $|V_{ub}|$ using baryonic decays
• Electron Identification in Belle
• Evidence for B0->pi0pi0
• Semileptonic B decays to excited charmed mesons
• B_l4 decays and the extraction of |V_ub|
• Study of B --> pi l nu and B --> rho l nu Decays and Determination of |V_ub|
• Study of Exclusive B->X_u l nu Decays and Extraction of |V_{ub}| using Full Reconstruction Tagging at the Belle Experiment
• B -> X_u l nu decay distributions to order alpha_s
• Branching fraction and form-factor shape measurements of exclusive charmless semileptonic B decays, and determination of |V_{ub}|
• A Hierarchical NeuroBayes-based Algorithm for Full Reconstruction of B Mesons at B Factories
• B->eta(') Form Factors in QCD
• Measurement of $B\to \rho \ell \nu$ Decay and $|V_{ub}|$
• Disentangling the Decay Observables in $B^{-}\to {\pi }^{+}{\pi }^{-}{\ell }^{-}{\bar{\nu }}_{\ell }$
• $B\to \pi \pi$ Form Factors from Light-Cone Sum Rules with $B$-meson Distribution Amplitudes
• Measurements of branching fractions and $q^2$ distributions for $B\to \pi \ell \nu$ and $B\to \rho \ell \nu$ Decays with $B\to D^{(\ast )}\ell \nu$ Decay Tagging
• B to Light Tensor Meson Form Factors Derived from Light-Cone Sum Rules
• Measurement of Inclusive Production of Neutral Pions from Upsilon(4S) Decays
• Chiral dynamics, S-wave contributions and angular analysis in $D\to \pi \pi \ell \bar{\nu }$
• Reweighting of the form factors in exclusive B --> X ell nu decays

Cited by in corpus (6)

• $B\to \rho l\bar{\nu }$ and $\omega l\bar{\nu }$ in and beyond the Standard Model: Improved predictions and $|V_{ub}|$
• $B\to \rho \ell \bar{\nu }$ resonance form factors from $B\to \pi \pi \ell \bar{\nu }$ in lattice QCD
• Semileptonic baryonic $B$ decays
• A model-independent parameterization of $B\to \pi \pi \ell \nu$ decays
• Role of $\rho -\omega$ interference in semileptonic $B\to {\pi }^{+}{\pi }^{-}\ell {\bar{\nu }}_{\ell }$ decays
• Recent progress in decays of $b$ and $c$ hadrons