The sensitivity to the $B_{s}-\overline{B}_{s}$ mixing phase at LHCb

We present the sensitivity to the Bs--Bsbar mixing phase phi_s at LHCb, using decays proceeding through bbar -> cbar c sbar quark-level transitions. The performance is assessed by means of toy Monte Carlo simulations, parameterized using the results of full Monte Carlo studies. Both the bbar -> cbar c sbar decays to pure (B_s -> eta_c phi, B_s -> D_s D_s, B_s -> J/psi eta) and to an admixture of CP eigenstates (B_s -> J/psi phi) are considered, and used to probe the Bs--Bsbar mixing phase through a time-dependent mixing-induced CP measurement.