Observation of e + e - → D s+ D(∗) 0 K - and study of the P-wave Ds mesons

Studies of e + e - → D s+ D(∗) 0 K - and the -wave charmed-strange mesons are performed based on an e + e - collision data sample corresponding to an integrated luminosity of 567 pb -1 collected with the BESIII detector at √s = 4.600 GeV. The processes of e + e - → D s+ D(∗) 0 K - and D s+ D(∗) 0 K - are observed for the first time and are found to be dominated by the modes D s+ D s1 (2536) - and D s+ D s2 ∗ (2573) - , respectively. The Born cross sections are measured to be σ B (e + e - → D s+ D(∗) 0 K - ) = (10.1 ± 2.3 ± 0.8) pb and σ B (e + e - → D s+ D(∗) 0 K - ) = (19.4 ± 2.3 ± 1.6) pb, and the products of Born cross section and the decay branching fraction are measured to be σ B (e + e - → D s+ D s1 (2536) - + c.c.). ℬ(D s1 (2536) - → D 0 ∗ K - ) = (7.5 ± 1.8 ± 0.7) pb and σ B (e + e - → D s+ D s2 ∗(2573) - + c.c.). ℬ(D∗ s2 (2573) - → D 0 K - ) = (19.7 ± 2.9 ± 2.0) pb. For the D s1 (2536) -1 and D∗ s2 (2573) - mesons, the masses and widths are measured to be M(D s1 (2536) -1 ) = (2537.7 ± 0.5 ± 3.1) MeV/c 2 , λ(D∗ s2 (2573) -1 ) = (17.2 ± 3.6 ± 1.1) MeV. The spin-parity of the D∗ s2 (2573) - meson is determined to be J p = 2 + . In addition, the processes e + e - → D s+ D(∗) 0 K - are searched for using the data samples taken at four (two) center-of-mass energies between 4.416 (4.527) and 4.575 GeV, and upper limits at the 90% confidence level on the cross sections are determined.