Measurement of the CP violating phase phi(s) in (B)over-bar(s)(0) -> J/psi f(0)(980)

Measurement of mixing-induced CP violation in (B) over bar (0)(s) decays is of prime importance in probing new physics. So far only the channel (B) over bar (0)(s) -> J/psi phi 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/psi f(0)(980), where f(0)(980) -> pi(+)pi(-). A time-dependent fit of the data with the (B) over bar (0)(s) lifetime and the difference in widths of the heavy and light eigenstates constrained to the values obtained from (B) over bar (0)(s) -> J/psi phi yields a value of the CP violating phase of -0.44 +/- 0.44 +/- 0.02 rad, consistent with the Standard Model expectation. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.