Measurement of Ds + and Ds*+ production in B meson decays and from continuum e+e- annihilation at √s = 10.6 GeV

New measurements of Ds + and Ds*+ meson production rates from B decays and from qq̄ continuum events near the Y(4S) resonance are presented. Using 20.8 fb-1 of data on the Y(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B→Ds + X)=(10.93±0.19±0.58±2.73)% and B(B→Ds*+X)=(7.9±0.8±0.7 ±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds +→φπ+ branching fraction uncertainty. The production cross sections σ(e+e- →Ds +X) × B(Ds +→φπ+)=7.55±0.20 ±0.34 pb and σ(e+e-→Ds *±X) × B(Ds +→φπ+) = 5.8±0.7±0.5 pb are measured at center-of-mass energies about 40 MeV below the Y(4S) mass. The branching fractions ΣB(B→Ds (*)+ D̄(*))=(5.07±0.14±0.30±1.27)% and ∑B(B→Ds *+D̄(*)) =(4.1±0.2±0.4±1.0)% are determined from the Ds (*)+ momentum spectra. The mass difference m(Ds +)-m(D+)=98.4±0.1 ±0.3 MeV/c2 is also measured.