Measurement of the time-dependent CP asymmetry in B0 -> J/{\psi} KS0   decays
  This Letter reports a measurement of the CP violation observables S_J/{\psi}KS0 and C_J/{\psi}KS0 in the decay channel B0 -> J/{\psi} KS0 performed with 1.0/fb of pp collisions at sqrt(s) = 7 TeV collected by the LHCb experiment. The fit to the data yields S_J/{\psi}KS0 = 0.73 +- 0.07 (stat) +- 0.04 (syst) and C_J/{\psi}KS0 = 0.03 +- 0.09 (stat) +- 0.01 (syst). Both values are consistent with the current world averages and within expectations from the Standard Model. 
LHCb collaboration: R. Aaij, C. Abellan Beteta, A. Adametz, B. Adeva,   M. Adinolfi, C. Adrover, A. Affolder, Z. Ajaltouni, ...
hep-ex