Measurement of the lifetime difference in the B0s system

Abstract

We present a study of the untagged decay B0s → J/ψ φ , using 450 pb−1 of data collected in Run II of Fermilab experiment DØ. In particular, we obtain an average lifetime difference in the (B0s , B0s ) system of 1.39+−001316 (stat)+−000102 (syst) ps, a relative width difference of the mass eigenstates, ∆Γ/Γ ≡ (ΓL − ΓH )/Γ, of 0.25+−002838 (stat)+−000304 (syst), and the CP-odd fraction at time zero, R = 0.16 ± 0.10 (stat) ± 0.02 (syst) .