Observation of the baryonic decay $\bar{B}^0 \to \Lambda^+_c \bar{p} K^- K^+$

TL;DR

This paper reports the first observation of a specific baryonic decay of the B meson, measuring its branching fraction with high significance, and sets an upper limit on a related resonant decay mode.

Contribution

The paper presents the first observation and measurement of the branching fraction of the baryonic decay b0 b0 b0 b0, b0 using data from the BABAR experiment, including detailed uncertainty analysis.

Findings

Branching fraction of b0 b0 b0 b0 measured as (2.5 1 0.4 0 0.2 0 6) imes 10^{-5}.

Observation significance of 5.0 standard deviations.

Upper limit for b0 b0 b0 b0 b0 b0 b0 at 90% CL is <1.2 imes 10^{-5}.

Abstract

We report the observation of the baryonic decay $\bar{B}^0 \to \Lambda^+_c \bar{p} K^- K^+$ using a data sample of $471 \times 10^6$ $B\bar{B}$ pairs produced in $e^+e^-$ annihilations at $\sqrt{s}=10.58 \mathrm{\,GeV}$. This data sample was recorded with the $BABAR$ detector at the PEP-II storage ring at SLAC. We find ${\cal B}\left(\bar{B}^0 \to \Lambda^+_c \bar{p} K^- K^+ \right) = \left(2.5 \pm 0.4_{(\text{stat})} \pm 0.2_{(\text{syst})}\pm 0.6_{{\cal B}\left(\Lambda^+_c\right)} \right) \times 10^{-5}$, where the uncertainties are statistical, systematic, and due to the uncertainty of the $\Lambda^+_c \to p K^- \pi^+$ branching fraction, respectively. The result has a significance corresponding to 5.0 standard deviations, including all uncertainties. For the resonant decay $\bar{B}^0 \to \Lambda^+_c \bar{p} \phi$, we determine the upper limit ${\cal B}\left(\bar{B}^0 \to \Lambda^+_c \bar{p} \phi \right) <1.2 \times 10^{-5}$ at $90\%$ confidence level.