A new technique to measure the ratio of b quark fragmentation fractions in $p\overline{p}$ collisions is described. Using a ${70-\mathrm{p}\mathrm{b}}^{\mathrm{-}1}$ sample of low-mass dimuon trigger data recorded with the Collider Detector at Fermilab, we identify B mesons by observing the double semileptonic decays $\overrightarrow{b}c\mu X$ with $\overrightarrow{c}s\mu X.\mathrm{}$ By counting the numbers of $K^{*}{\mathrm{}\left(892\right)\mathrm{}}^0,$ $K^{*}{\mathrm{}\left(892\right)\mathrm{}}^{+},$ and φ(1020) mesons produced in association with these muon pairs, we measure the ratio of strange to nonstrange B meson production to be $f_s{/(f}_u{+f}_d)=[21.0\pm 3.6\left(\mathrm{stat}{)}_{-3.0}^{+3.8\mathrm{}}\right(\mathrm{syst}\left)\right]\%.\mathrm{}$ This measurement is the most precise available from hadron collisions to date. Limits on the branching fractions of semileptonic charm meson decays with $K_1\mathrm{}\left(1270\right),$ $K_1^{*}\mathrm{}\left(1410\right),$ and $K_2^{*}\mathrm{}\left(1430\right)\mathrm{}$ mesons in the final state are also obtained.

• Received 4 March 1999

DOI:https://doi.org/10.1103/PhysRevD.60.092005