A flavour-tagged time-dependent angular analysis of decays is presented where the meson is reconstructed through its decay to an pair. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and\(8\text {\, Te V}\), corresponding to an integrated luminosity of\(3\text {\, fb}^{-1}\). The-violating phase and lifetime parameters of the system are measured to be\({\phi _ {{s}}}= 0.00\pm 0.28\pm 0.07\text {\, rad}\),\({\Delta\Gamma _ {{s}}}= 0.115\pm 0.045\pm 0.011\text {\, ps}^{-1}\) and\({\Gamma _ {{s}}}= 0.608\pm 0.018\pm 0.012\text {\, ps}^{-1}\) where the first uncertainty is statistical and the second systematic. This is the first time that-violating parameters are measured in the decay with an pair in the final state. The results are consistent with previous measurements in other channels and with the Standard Model predictions.