A time-dependent angular analysis of decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of collected during Run 1 of the LHC. The CP -violating phase and decay-width difference of the 470949a8a4a9690fd9c70b4"> system are measured to be i4" class="mathmlsrc">i4.gif&_user=111111111&_pii=S0370269316305226&_rdoc=1&_issn=03702693&md5=f30428e4d550321c1678b9029158e0bb">i4.gif"> and , respectively, where the first uncertainty is statistical and the second systematic. This is the first time that ϕs and ΔΓs have been measured in a decay containing the ψ(2S) resonance.