A search for time-dependent violation of the charge-parity symmetry in $D^0\to K^{+}{K}^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}$ decays is performed at the LHCb experiment using proton-proton collision data recorded from 2015 to 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of $6{\mathrm{fb}}^{-1}$. The $D^0$ meson is required to originate from a $D^{*}(2010{)}^{+}\to D^0{\pi }^{+}$ decay, such that its flavor at production is identified by the charge of the accompanying pion. The slope of the time-dependent asymmetry of the decay rates of $D^0$ and ${\overline{D}}^0$ mesons into the final states under consideration is measured to be $\mathrm{\Delta }{Y}_{K^{+}{K}^{-}}=(-2.3\pm 1.5\pm 0.3)\times {10}^{-4}$, $\mathrm{\Delta }{Y}_{{\pi }^{+}{\pi }^{-}}=(-4.0\pm 2.8\pm 0.4)\times {10}^{-4}$, where the first uncertainties are statistical and the second are systematic. These results are compatible with the conservation of the charge-parity symmetry at the level of 2 standard deviations and improve the precision by nearly a factor of 2.

中文翻译：

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在D0→K+K−和D0→π+π−衰减中搜索时间相关的CPviolation

寻找与时间相关的电荷奇偶对称性违反 $D^0\to {钾}^{+}{钾}^{-}$ 和 $D^0\to {\pi }^{+}{\pi }^{-}$ 在 LHCb 实验中使用 2015 年至 2018 年以 13 TeV 质心能量记录的质子 - 质子碰撞数据进行衰变，对应于积分光度 $6{\mathrm{脸书}}^{-1}$. 这$D^0$ 介子必须起源于 $D^{*}(\mathrm{2010年}{)}^{+}\to D^0{\pi }^{+}$衰变，这样它在生产时的味道就可以通过伴随的π介子的电荷来识别。衰减率随时间变化的不对称性的斜率$D^0$ 和 ${\overline{D}}^0$ 进入所考虑的最终状态的介子被测量为 $\mathrm{\Delta }{是}_{{钾}^{+}{钾}^{-}}=(-2.3\pm 1.5\pm 0.3)\times {10}^{-4}$, $\mathrm{\Delta }{是}_{{\pi }^{+}{\pi }^{-}}=(-4.0\pm 2.8\pm 0.4)\times {10}^{-4}$，其中第一个不确定性是统计性的，第二个是系统性的。这些结果与电荷奇偶对称性在 2 个标准差水平上的守恒相一致，并将精度提高了近 2 倍。