Measurement of the lifetime difference in the B_s⁰ system

Abstract

We present a study of the decay B_s⁰→J/ψø. We obtain the CP-odd fraction in the final state at time zero, R⊥=0.16± 0.10(stat)±0.02(syst), the average lifetime of the (B_s⁰, B‾ _s⁰) system, t‾ (B_s⁰)=1.39_-0.16^+0.13(stat)_-0.02 ^+0.01(syst) ps, and the relative width difference between the heavy and light mass eigenstates, ΔΓ/Γ‾=(Γ _L-Γ_H)/Γ‾=0.24_-0.38^+0.28(stat) _-0.04^+0.03(syst). With the additional constraint from the world average of the B_s⁰ lifetime measurements using semileptonic decays, we find t‾ (B_s⁰)=1.39±0.06 ps and ΔΓ/Γ‾ =0.25_-0.15^+0.14. For the ratio of the B_s⁰ and B⁰ lifetimes we obtain t‾(B_s⁰)/t(B⁰)=0.91±0.09(stat) ±0.003(syst).