Measurements of B lifetimes at LHCb

Measurements of the $B_s^0$ effective lifetime in decays to CP-odd and CP-even flavour specific final states allow to probe the width difference $\Delta \Gamma_s$ and the CP-violating phase $\phi_s$ of $B^0_s-\bar{B}^0_s$ mixing box-diagram. Measurements of the effective lifetime in the decay channels $B_s^0 \rightarrow K^+ K^-$ and $\bar{B}_s^0 \rightarrow J/\psi f_0(980)$ are presented, as well as a measurement of $\Delta \Gamma_s$ and $\Gamma_s$ performed by a tagged time-dependent angular analysis of $B_s^0 \rightarrow J/\psi \phi$ decays and a measurement of the sign of $\Delta \Gamma_s$, using data collected during 2011 with the LHCb detector.