Studies of CP-conserving and CP-violating Bs mixing parameters with the D0 experiment

This paper summarises the recent results of the Run IIa D0 experiment at the Tevatron Collider at Fermilab on the observable parameters of the $B_{s}$ meson. A measurement of the branching fraction $B_s->D_s^{(*)}D_s^{(*)}$ is reported, which provides an estimate of the width difference $\Delta\Gamma_{s}^{CP}/\Delta\Gamma_{s}$. Through the decay $B_{s} \to J/\psi \phi$ the width difference $\Delta\Gamma_{s}$ is extracted, and for the first time a constraint is set on the CP-violating phase $\phi_{s}$, although a four-fold ambiguity remains. This result is combined with other D0 measurements to yield $\Delta\Gamma_{s}=0.13\pm0.09 {\rm ps^{-1}}$, $\phi_{s} = -0.70^{+0.47}_{-0.39}$.