Observation of a new excited charm-strange meson $D_{s1}(2933{)}^{+}$ in $B^0\to D^{+}{D}^{-}{K}^{+}{\pi }^{-}$ decays

A new excited charm-strange meson is observed through an amplitude analysis of the full phase space of $B^0\to D^{+}{D}^{-}{K}^{+}{\pi }^{-}$ decays. The analysis is based on a proton-proton collision data sample collected by the \lhcb experiment at a center-of-mass energy $\sqrt{s}=13\text{TeV}$, corresponding to an integrated luminosity of $5.4{\text{fb}}^{-1}$. The statistical significance of the new state exceeds $10$ standard deviations. Its Breit–Wigner mass and width are measured to be $m_0={2933}_{-5}^{+6}(\text{stat}{)}_{-3}^{+4}(\text{syst})\text{MeV}$ and ${\mathrm{\Gamma }}_0={72}_{-12}^{+18}(\text{stat}{)}_{-10}^{+\phantom{0}7}(\text{syst})\text{MeV}$, respectively, and its spin-parity quantum numbers are determined to be $J^P=1^{+}$. This new meson, denoted as $D_{s1}(2933{)}^{+}$, is a candidate for a $D_s(2P_1^{(\mathrm{\prime })}{)}^{+}$ state.