Semileptonic $B-\to p\bar{p} \ell-\bar{\nu}_\ell$ decays

TL;DR

This paper calculates the branching ratios of specific semileptonic baryonic B decays, finding they are within reach of current experiments, and significantly larger than previous estimates for inclusive modes.

Contribution

It provides the first detailed Standard Model predictions for the branching ratios of $B^- o p ar p \, ext{and} \, ar u_ ext{ell}$ decays, showing they are observable at B-factories.

Findings

Branching ratios are about (1.0, 1.0, 0.5) x 10^{-4} for e, μ, τ modes.

Electron mode close to CLEO's upper limit.

Results are 10-100 times larger than previous inclusive mode estimates.

Abstract

We study the four-body exclusive semileptonic baryonic $\bar B$ decays of $B^-\to p\bar p \ell^- \bar\nu_{\ell}$ ($\ell=e,\mu,\tau$) in the standard model. We find that their decay branching ratios are about $(1.0, 1.0,0.5)\times 10^{-4}$, respectively. In particular, the electron mode is close to the corresponding CLEO's upper limit of $5.2\times 10^{-3}$, while all results are about one or two orders of magnitude larger than the previous estimated values for the inclusive modes of $\bar B\to {\bf B\bar B'}\ell \bar \nu$. Clearly, both B-factories of Belle and BaBar should be able to observe these exclusive four-body modes.