Observation of Overlapping Spin-1 and Spin-3 ¯D0K− Resonances at Mass 2.86 GeV/c2

Abstract

The resonant substructure of B 0 s → ¯ D 0 K − π + decays is studied using a data sample corresponding to an integrated luminosity of 3.0 fb − 1 of p p collision data recorded by the LHCb detector. An excess at m ( ¯ D 0 K − ) ≈ 2.86 GeV / c 2 is found to be an admixture of spin-1 and spin-3 resonances. Therefore, the D ∗ s J ( 2860 ) − state previously observed in inclusive e + e − → ¯ D 0 K − X and p p → ¯ D 0 K − X processes consists of at least two particles. This is the first observation of a heavy flavored spin-3 resonance, and the first time that any spin-3 particle has been seen to be produced in B decays. The masses and widths of the new states and of the D ∗ s 2 ( 2573 ) − meson are measured, giving the most precise determinations to date.