Evidence for Semileptonic B- to p pbar l nubar Decays

Abstract

We find evidence for the semileptonic baryonic decay $B^{-}\to p\bar{p}{\ell }^{-}{\bar{\nu }}_{\ell }$ ($\ell =e,\mu$), based on a data sample of 772 million $B\bar{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy electron-positron collider. A neural-network based hadronic $B$-meson tagging method is used in this study. The branching fraction of $B^{-}\to p\bar{p}{\ell }^{-}{\bar{\nu }}_{\ell }$ is measured to be $(5.8_{-2.1}^{+2.4}\text{(stat.)}\pm 0.9\text{(syst.)})\times 10^{-6}$ with a significance of 3.2$\sigma$, where lepton universality is assumed. We also estimate the corresponding upper limit: $\mathcal{B}(B^{-}\to p\bar{p}{\ell }^{-}{\bar{\nu }}_{\ell })<9.6\times 10^{-6}$ at the 90% confidence level. This measurement helps constrain the baryonic transition form factor in B decays.

12 pages, 4 figures, submitted to Phys.Rev.Lett

References in corpus (2)

• Study of B --> pi l nu and B --> rho l nu Decays and Determination of |V_ub|
• Study of the decay mechanism for B+ to p pbar K+ and B+ to p pbar pi+

Cited by in corpus (8)

• Semitauonic $b$-hadron decays: A lepton flavor universality laboratory
• Violation of PCAC and two-body baryonic $B$ and $D_s$ decays
• The semileptonic baryonic decay $D_s^{+}\to p\bar{p}{e}^{+}{\nu }_e$
• Three-body charmless baryonic ${\bar{B}}_s^0$ decays
• Progress on semi-leptonic $B_{(s)}$ decays
• Determination of $|V_{ub}|$ from exclusive baryonic $B$ decays
• Charmless Semileptonic B Decays at e+e- Colliders
• Study of $B\to p\bar{p}\pi \pi$