First observation of the rare $B^{+}\to D^{+}{K}^{+}\ddot{I}{€}^{-}$ decay

Abstract

The $B^{+}\to D^{+}{K}^{+}\ddot{I}{€}^{-}$ decay is observed in a data sample corresponding to $3.0{\mathrm{fb}}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. The signal significance is $8\ddot{I}ƒ$ and the branching fraction is measured to be $\mathcal{B}\left(B^{+}\to D^{+}{K}^{+}\ddot{I}{€}^{-}\right)=(5.31\pm 0.90\pm 0.48\pm 0.35)\times 10^{-6}$, where the uncertainties are statistical, systematic and due to the normalisation mode $B^{+}\to D^{-}{K}^{+}\ddot{I}{€}^{+}$, respectively. The Dalitz plot appears to be dominated by broad structures. Angular distributions are exploited to search for quasi-two-body contributions from $B^{+}\to D_2^{\ast }(2460{)}^0{K}^{+}$ and $B^{+}\to D^{+}{K}^{\ast }(892{)}^0$ decays. No significant signals are observed and upper limits are set on their branching fractions.

19 pages, 4 figures, submitted to Phys. Rev. D. (R). All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-054.html. Updated following erratum: 10.1103/PhysRevD.93.119902