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

Abstract

Studies of e+e- ? Ds+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- ? Ds+D(?)0 K- and Ds+D(?)0 K- are observed for the first time and are found to be dominated by the modes Ds+ Ds1 (2536)- and Ds+ Ds2? (2573)-, respectively. The Born cross sections are measured to be ?B (e+e- ? Ds+D(?)0 K-) = (10.1 ± 2.3 ± 0.8) pb and ?B (e+e- ? Ds+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 ?B (e+e- ? Ds+Ds1(2536)- + c.c.). ?(Ds1(2536)- ? D0? K-) = (7.5 ± 1.8 ± 0.7) pb and ?B(e+e- ? Ds+Ds2?(2573)- + c.c.). ?(D?s2 (2573)- ? D0K-) = (19.7 ± 2.9 ± 2.0) pb. For the Ds1(2536)-1 and D?s2 (2573)- mesons, the masses and widths are measured to be M(Ds1(2536)-1) = (2537.7 ± 0.5 ± 3.1) MeV/c2, ?(D?s2(2573)-1) = (17.2 ± 3.6 ± 1.1) MeV. The spin-parity of the D?s2 (2573)- meson is determined to be Jp = 2+. In addition, the processes e+e- ? Ds+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.