Bs0 lifetime measurement in the C P -odd decay channel Bs0→J /ψ f 0(980 )

The lifetime of the B_s⁰ meson is measured in the decay channel B_s⁰→J /ψ π⁺π^- with 880 ≤M_π⁺π^-≤1080 MeV /c² , which is mainly a C P -odd state and dominated by the f₀(980 ) resonance. In 10.4 fb^-1 of data collected with the D0 detector in Run II of the Tevatron, the lifetime of the B_s⁰ meson is measured to be τ (B_s⁰)=1.70 ±0.14 (stat ) ±0.05 (syst) ps . Neglecting C P violation in B_s⁰/B_¯s⁰ mixing, the measurement can be translated into the width of the heavy mass eigenstate of the B_s⁰, Γ_H=0.59 ±0.05 (stat ) ±0.02 (syst ) ps^-1 .