Measurement of the ${\bar{B}}_s^0\to D_s^{-}{D}_s^{+}$ and ${\bar{B}}_s^0\to D^{-}{D}_s^{+}$ effective lifetimes

Abstract

The first measurement of the effective lifetime of the ${\bar{B}}_s^0$ meson in the decay ${\bar{B}}_s^0\to D_s^{-}{D}_s^{+}$ is reported using a proton-proton collision dataset, corresponding to an integrated luminosity of 3 fb${}^{-1}$, collected by the LHCb experiment. The measured value of the ${\bar{B}}_s^0\to D_s^{-}{D}_s^{+}$ effective lifetime is $1.379\pm 0.026\pm 0.017$ ps, where the uncertainties are statistical and systematic, respectively. This lifetime translates into a measurement of the decay width of the light ${\bar{B}}_s^0$ mass eigenstate of Γ_L$=0.725\pm 0.014\pm 0.009$ ps${}^{-1}$. The ${\bar{B}}_s^0$ lifetime is also measured using the flavor-specific ${\bar{B}}_s^0\to D^{-}{D}_s^{+}$ decay to be $1.52\pm 0.15\pm 0.01\mathrm{ps}$.

8 pages, 4 figures