Analysis of decay-time dependence of angular distributions in$B^0_s \rightarrow J/\psi \phi$ and a measurement of the lifetime difference between $B^0_s$ CP eigenstates

We study the decay processes $B^0_s \rightarrow J/\psi \phi$ and $B^0_d \rightarrow J/\psi K^*$ using the first 440~pb$^{-1}$ of D\O\ data. We measure the average lifetime and the relative lifetime difference for the $B^0_s$ system. We also measure the $B^0_d$ lifetime (assuming a single-exponential decay), and the $P$-wave fraction $R_{\perp}$ for $B^0_s$ and $B^0_d$.