Measurement of the CP violating phase φ<inf>s</inf> in B-<inf>s</inf>⁰→J/ψf0(980)

Measurement of mixing-induced CP violation in B-s0 decays is of prime importance in probing new physics. So far only the channel B- _s ⁰→J/ψφ has been used. Here we report on a measurement using an LHCb data sample of 0.41 fb ^-1, in the CP odd eigenstate J/ψf ₀(980), where f ₀(980)→π ⁺π ^-. A time-dependent fit of the data with the B-s0 lifetime and the difference in widths of the heavy and light eigenstates constrained to the values obtained from B-s0→J/ψφ yields a value of the CP violating phase of -0.44±0.44±0.02 rad, consistent with the Standard Model expectation.