Abstract: A novel machine-learning-based flavor-tagging algorithm combining same-side and opposite-side tagging is used to obtain the equivalent of 27 500 tagged B_{s}^{0}->J/uo(1020) decays from pp collisions at sqrt[s]=13 TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 96.5 fb^{-1}. A time- and flavor-dependent angular analysis of the u^{+}u^{-}K^{+}K^{-} final state, consistent with a o(1020)->K^{+}K^{-} decay, is used to measure parameters of the B_{s}^{0}-B[over ¯]_{s}^{0} system. The weak phase is measured to be o_{s}=-73±22(stat)±10(syst) mrad, which, combined with the sqrt[s]=8 TeV CMS result, gives o_{s}=-75±23 mrad. This value differs from zero by 3.2 standard deviations, providing the first evidence for mixing-induced CP violation in B_{s}^{0}->J/uo(1020) decays. All measured physics parameters are found to agree with standard model predictions where available.

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