论文标题
$ d^0 \ to k^-k^+$衰减的时间集成$ c \！p $不对称的测量
Measurement of the time-integrated $C\!P$ asymmetry in $D^0\to K^- K^+$ decays
论文作者
论文摘要
使用Proton-Proton碰撞数据测量了时间整合的$ C \！P $非对称$ D^0 \ to K^-k^+$，对应于5.7 fb $^{ - 1} $的集成亮度，在13 tev fact the lhcb detector的13 tev tev collected collected。 $ d^0 $介子必须源自迅速产生的$ d^{*+} \至d^0π^+$衰减，并且使用伴侣的费用来确定生产中魅力梅森的风味。测量时间集成的$ c \！p $不对称是\ begin {align*} \ mathcal {a} _ {c \！p}（k^-k^+）= \ left [6.8] \ end {align*} $ d^0 \ in $ d^0 \ to k^ - k^+$ and $ d^0 \toπ^-π^+$衰减，$ a_ {k^-k^-k^+}^{d}^{d} $ \ Mathcal {a} _ {c \！p}（k^-k^+）$带有时间整合$ c \！p $不对称差异，$Δ\ m nathcal {a} _} _ {c \！p} = \！ （k^-k^+） - \ Mathcal {a} _ {c \！ \ end {alignat*} \ begin {alignat*} {2} a_ {π^-π^+}^{d}^{d}＆=（23.2 \ pm 6.1）\ times 10^{ - 4}，\ end End {alignat*}，并带有相关系数与corelation corleLation corefitive对应到$ $ρ= 0.88 $。这些结果与$ c \！p $对称性的兼容性分别为1.4和3.8标准偏差，分别为$ d^0 \ to K^ - k^+$和$ d^0 \toπ^-π^-π^+$衰减。这是特定$ d^0 $衰减中直接$ c \！p $违规的第一个证据。
The time-integrated $C\!P$ asymmetry in the Cabibbo-suppressed decay $D^0\to K^-K^+$ is measured using proton-proton collision data, corresponding to an integrated luminosity of 5.7 fb$^{-1}$ collected at a center-of-mass energy of 13 TeV with the LHCb detector. The $D^0$ mesons are required to originate from promptly produced $D^{*+}\to D^0π^+$ decays and the charge of the companion pion is used to determine the flavor of the charm meson at production. The time-integrated $C\!P$ asymmetry is measured to be \begin{align*} \mathcal{A}_{C\!P}(K^-K^+) = \left[6.8 \pm 5.4 \text{ (stat)} \pm 1.6 \text{ (syst)} \right]\times 10^{-4}. \end{align*} The direct $C\!P$ asymmetries in $D^0\to K^- K^+$ and $D^0\toπ^-π^+$ decays, $a_{K^-K^+}^{d}$ and $a_{π^-π^+}^{d}$, are derived by combining $\mathcal{A}_{C\!P} (K^-K^+)$ with the time-integrated $C\!P$ asymmetry difference, $Δ\mathcal{A}_{C\!P} =\mathcal{A}_{C\!P} (K^-K^+)-\mathcal{A}_{C\!P} (π^-π^+)$, giving \begin{alignat*}{2} a_{K^-K^+}^{d} &= (\phantom{2}7.7 \pm 5.7) \times 10^{-4}, \end{alignat*} \begin{alignat*}{2} a_{π^-π^+}^{d} &= (23.2 \pm 6.1) \times 10^{-4}, \end{alignat*} with a correlation coefficient corresponding to $ρ=0.88$. The compatibility of these results with $C\!P$ symmetry is 1.4 and 3.8 standard deviations for $D^0\to K^- K^+$ and $D^0\toπ^-π^+$ decays, respectively. This is the first evidence for direct $C\!P$ violation in a specific $D^0$ decay.
