Measurement of the B0s Lifetime in the Flavor-Specific Decay Channel B0s→D−sμ+νX

Abstract

We present an updated measurement of the B0s lifetime using the semileptonic decays B0s→D−sμ+νX, with D−s→ϕπ− and ϕ→K+K− (and the charge conjugate process). This measurement uses the full Tevatron Run II sample of proton-antiproton collisions at s√=1.96 TeV, comprising an integrated luminosity of 10.4 fb−1. We find a flavor-specific lifetime τfs(B0s)=1.479±0.010(stat)±0.021(syst) ps. This technique is also used to determine the B0 lifetime using the analogous B0→D−μ+νX decay with D−→ϕπ− and ϕ→K+K−, yielding τ(B0)=1.534±0.019(stat)±0.021(syst) ps. Both measurements are consistent with the current world averages, and the B0s lifetime measurement is one of the most precise to date. Taking advantage of the cancellation of systematic uncertainties, we determine the lifetime ratio τfs(B0s)/τ(B0)=0.964±0.013(stat)±0.007(syst).