A time-dependent angular analysis of den">de"> decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of den">de"> collected during Run 1 of the LHC. The CP -violating phase and decay-width difference of the den">de"> system are measured to be den">de"> and den">de">, respectively, where the first uncertainty is statistical and the second systematic. This is the first time that de8c9c6202c699c" title="Click to view the MathML source">ϕsden">de"> and ΔΓsden">de"> have been measured in a decay containing the de8f1092f2090a62ab2b48a9e" title="Click to view the MathML source">ψ(2S)den">de"> resonance.