Measurement Of D-S(+) Meson Production In Z Decays And Of The (B)Over-Bar(S)(0) Lifetime

D-s(+) mesons produced in Z(0) --> b (b) over bar events were separated from the Z(0) --> c (c) over bar component using a lifetime tag. Using a sample of 1.5 million hadronic Z decays collected with the ALEPH detector the (B) over bar(s)(0) and D-s(+) yields have been measured:[GRAPHICS]The (B) over bar(2)(0) lifetime was measured in a (B) over bar(s)(0) enriched samplereconstructing the decay length from the vertex of the D-s(+) with a hadron from the (B) over bar(0)(s) decay, The result obtained is:[GRAPHICS]