Semileptonic baryonic $B$ decays

TL;DR

This paper analyzes semileptonic baryonic B decays using new form factors, providing updated branching ratios that align with current data and making predictions for future experimental tests at LHCb.

Contribution

The study introduces improved transition form factors and offers new predictions for branching ratios of semileptonic baryonic B decays, some of which are accessible to LHCb.

Findings

Measured ${ m BR}(B^- o par p \mu^-ar u_\mu)$ matches current data.

Calculated ${ m BR}(B^- o \Lambdaar p u ar u)$ is 20 times smaller than previous estimates.

Predicted ${ m BR}$ for $ar B^0_s$ decays are within reach of LHCb detection.

Abstract

We study the semileptonic $B\to{\bf B\bar B'}L\bar L'$ decays with $\bf B\bar B'$ ($L\bar L'$) representing a baryon (lepton) pair. Using the new determination of the $B\to{\bf B\bar B'}$ transition form factors, we obtain ${\cal B}(B^-\to p\bar p \mu^-\bar \nu_\mu) =(5.4\pm 2.0)\times 10^{-6}$ agreeing with the current data. Besides, ${\cal B}(B^-\to \Lambda\bar p \nu \bar \nu)=(3.5\pm 1.0)\times 10^{-8}$ is calculated to be 20 times smaller than the previous prediction. In particular, we predict ${\cal B}(\bar B^0_s\to p\bar \Lambda e^- \bar \nu_e,p\bar \Lambda \mu^- \bar \nu_\mu,p\bar \Lambda \tau^- \bar \nu_\tau) =(2.1\pm 0.6,2.1\pm 0.6,1.7\pm 1.0)\times 10^{-6}$ and ${\cal B}(\bar B^0_s\to \Lambda\bar \Lambda \nu\bar \nu)=(0.8\pm 0.2)\times 10^{-8}$, which can be accessible to the LHCb experiment.