Production of D-s(**) mesons in hadronic Z decays

The production rates of the orbitally excited D-s** mesons, D-s1(+/-) and D-s2(*+/-), are measured with the 4.1 million hadronic Z decays recorded by the ALEPH detector during 1991-1995. The D-s** mesons are reconstructed in the decay modes D-s1(+) --> (D*+K0), D-s1(+) --> (DK+)-K-*0 and D-s2(*+) --> (DK+)-K-0. The production rate of the D-s1(+/-) is measured to be f (Z --> D-s1(+/-)) = (0.52 +/- 0.09 +/- 0.06)%, under the assumption that the two considered decay modes of the D-s1(+/-) saturate the branching ratio. The production rate of the D-s2(*+/-) is determined to be f (Z --> D-s2(*+/-)) = (0.83 +/- 0.29(-0.13)(+0.17))%, assuming that the branching fraction of the decay D-s2(*+) --> (DK+)-K-0 is 45%. The production rates in Z --> c (c) over bar and Z --> b (b) over bar decays are measured separately. (C) 2002 Elsevier Science B.V. All rights reserved.