First observation and amplitude analysis of the $B^{-}\to D^{+}K^{-}\pi^{-}$ decay

TL;DR

This paper reports the first observation and detailed amplitude analysis of the decay $B^{-}\to D^{+}K^{-}\pi^{-}$, measuring its branching fraction and resonant substructure, including the spin of the $D_{J}^{*}(2760)^{0}$ resonance.

Contribution

It provides the first observation of the decay and performs an amplitude analysis to identify resonant contributions and determine the spin of the $D_{J}^{*}(2760)^{0}$ resonance.

Findings

Branching fraction measured as (7.31 ± 0.19 ± 0.22 ± 0.39) × 10^{-5}

Resonant contributions from $D_{0}^{*}(2400)^{0}$, $D_{2}^{*}(2460)^{0}$, and $D_{J}^{*}(2760)^{0}$

The $D_{J}^{*}(2760)^{0}$ resonance has spin 1

Abstract

The $B^{-}\to D^{+}K^{-}\pi^{-}$ decay is observed in a data sample corresponding to $3.0~\rm{fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. Its branching fraction is measured to be ${\cal B}(B^{-}\to D^{+}K^{-}\pi^{-}) = (7.31 \pm 0.19 \pm 0.22 \pm 0.39) \times 10^{-5}$ where the uncertainties are statistical, systematic and from the branching fraction of the normalisation channel $B^{-}\to D^{+}\pi^{-}\pi^{-}$, respectively. An amplitude analysis of the resonant structure of the $B^{-}\to D^{+}K^{-}\pi^{-}$ decay is used to measure the contributions from quasi-two-body $B^{-}\to D_{0}^{*}(2400)^{0}K^{-}$, $B^{-}\to D_{2}^{*}(2460)^{0}K^{-}$, and $B^{-}\to D_{J}^{*}(2760)^{0}K^{-}$ decays, as well as from nonresonant sources. The $D_{J}^{*}(2760)^{0}$ resonance is determined to have spin~1.