First observation of the decay $B^0 \rightarrow D^0 \overline{D}{}^0 K^+ \pi^-$

TL;DR

This paper reports the first observation and measurement of the branching fraction of the decay $B^0 ightarrow D^0 ar{D}^0 K^+ \pi^-$ using LHCb data, providing new insights into charm spectroscopy and rare decay processes.

Contribution

The paper presents the first observation and precise measurement of the decay $B^0 ightarrow D^0 ar{D}^0 K^+ \pi^-$, expanding understanding of B meson decay modes.

Findings

Branching fraction ratio $ ext{R} = (14.2 \pm 1.1 ext{(stat)} \pm 1.0 ext{(syst)}) ext{ extperthousand}$.

Absolute branching fraction $ ext{B} = (3.50 \pm 0.27 ext{(stat)} \pm 0.26 ext{(syst)} \pm 0.30) imes 10^{-4}$.

First observation of this decay mode.

Abstract

The first observation of the decay $B^0 \rightarrow D^0 \overline{D}{}^0 K^+ \pi^-$ is reported using proton-proton collision data corresponding to an integrated luminosity of 4.7 $\mathrm{fb}^{-1}$ collected by the LHCb experiment in 2011, 2012 and 2016. The measurement is performed in the full kinematically allowed range of the decay outside of the $D^{*-}$ region. The ratio of the branching fraction relative to that of the control channel $B^0 \rightarrow D^{*-} D^0 K^+$ is measured to be $\mathcal{R} = (14.2 \pm 1.1 \pm 1.0)\%$, where the first uncertainty is statistical and the second is systematic. The absolute branching fraction of $B^0 \rightarrow D^0 \overline{D}{}^0 K^+ \pi^-$ decays is thus determined to be $\mathcal{B}(B^0 \rightarrow D^0 \overline{D}{}^0 K^+ \pi^-) = (3.50 \pm 0.27 \pm 0.26 \pm 0.30) \times 10^{-4}$, where the third uncertainty is due to the branching fraction of the control channel. This decay mode is expected to provide insights to spectroscopy and the charm-loop contributions in rare semileptonic decays.