Search for the decay $B^- \rightarrow \Lambda_c^+ \bar{p} \ell^- \bar{\nu}_{\ell}$ with the BABAR detector

TL;DR

This paper reports a search for a specific semileptonic baryonic B decay using the complete BABAR dataset, setting upper limits on its branching fraction and comparing results with theoretical predictions.

Contribution

First search for the decay $B^- ightarrow ext{Lambda}_c^+ ar{p} ext{lepton}^- ar{ u}_{ ext{lepton}}$ with new upper limits based on the full BABAR data set.

Findings

Upper limits on branching fractions were established.

Results show slight tension with existing theoretical predictions.

No definitive observation of the decay was made.

Abstract

This work presents the search for the semileptonic baryonic B decay $B^- \rightarrow \Lambda_c^+ \bar{p} \ell^- \bar{\nu}_{\ell}$. The used data comprises the complete BABAR data set of $470 \cdot 10^{6}$ $B\bar{B}$ events, collected at the SLAC National Accelerator Laboratory. Using a pole-model decay simulation, we obtain upper limits with $90\%$ confidence level of $B(B^- \rightarrow \Lambda_c^+ \bar{p} e^- \bar{\nu}_{e})\cdot \frac{B(\Lambda_c^+ \rightarrow p K^- \pi^+)}{5\%} < 1.2 \times 10^{-4}$, $B(B^- \rightarrow \Lambda_c^+ \bar{p} \mu^- \bar{\nu}_{\mu})\cdot \frac{B(\Lambda_c^+ \rightarrow p K^- \pi^+)}{5\%} < 2.5 \times 10^{-4}$, $B(B^- \rightarrow \Lambda_c^+ \bar{p} \ell^- \bar{\nu}_{\ell})\cdot \frac{B(\Lambda_c^+ \rightarrow p K^- \pi^+)}{5\%} < 1.0 \times 10^{-4}$. These results are in slight tension with predictions based on the measurement of $B^- \rightarrow \bar{p} p \ell^- \bar{\nu}_{\ell}$ and $B^- \rightarrow \Lambda_c^+ \bar{p} \pi^-$.