Improved measurement of the strong-phase difference ${\delta }_D^{K\pi }$ in quantum-correlated $D\bar{D}$ decays

Abstract

The decay $D\to K^{-}{\pi }^{+}$ is studied in a sample of quantum-correlated $D\bar{D}$ pairs, based on a data set corresponding to an integrated luminosity of 2.93\,fb${}^{-1}$ collected at the $\psi (3770)$ resonance by the BESIII experiment. The asymmetry between $CP$-odd and $CP$-even eigenstate decays into $K^{-}{\pi }^{+}$ is determined to be ${\mathcal{A}}_{K\pi }=0.132\pm 0.011\pm 0.007$, where the first uncertainty is statistical and the second is systematic. This measurement is an update of an earlier study exploiting additional tagging modes, including several decay modes involving a $K_L^0$ meson. The branching fractions of the $K_L^0$ modes are determined as input to the analysis in a manner that is independent of any strong phase uncertainty. Using the predominantly $CP$-even tag $D\to {\pi }^{+}{\pi }^{-}{\pi }^0$ and the ensemble of $CP$-odd eigenstate tags, the observable ${\mathcal{A}}_{K\pi }^{\pi \pi {\pi }^0}$ is measured to be $0.130\pm 0.012\pm 0.008$. The two asymmetries are sensitive to $r_D^{K\pi }\cos {\delta }_D^{K\pi }$, where $r_D^{K\pi }$ and ${\delta }_D^{K\pi }$ are the ratio of amplitudes and phase difference, respectively, between the doubly Cabibbo-suppressed and Cabibbo-favoured decays. In addition, events containing $D\to K^{-}{\pi }^{+}$ tagged by $D\to K_{S,L}^0{\pi }^{+}{\pi }^{-}$ are studied in bins of phase space of the three-body decays. This analysis has sensitivity to both $r_D^{K\pi }\cos {\delta }_D^{K\pi }$ and $r_D^{K\pi }\sin {\delta }_D^{K\pi }$. A fit to ${\mathcal{A}}_{K\pi }$, ${\mathcal{A}}_{K\pi }^{\pi \pi {\pi }^0}$ and the phase-space distribution of the $D\to K_{S,L}^0{\pi }^{+}{\pi }^{-}$ tags yields ${\delta }_D^{K\pi }=\left(187.6{}_{-9.7}^{+8.9}{}_{-6.4}^{+5.4}\right)$ degrees, where external constraints are applied for $r_D^{K\pi }$ and other relevant parameters. This is the most precise measurement of ${\delta }_D^{K\pi }$ in quantum-correlated $D\bar{D}$ decays.

Submitted to EPJC

References in corpus (7)

• Observation of $CP$ violation in charm decays
• On $SU(3{)}_F$ Breaking through Final State Interactions and CP Asymmetries in $D\to PP$ Decays
• First determination of the $CP$ content of $D\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ and updated determination of the $CP$ contents of $D\to {\pi }^{+}{\pi }^{-}{\pi }^0$ and $D\to K^{+}{K}^{-}{\pi }^0$
• Measurement of the $D\to K^{-}{\pi }^{+}$ strong phase difference in $\psi (3770)\to D^0\overline{D}{}^0$
• Mixing and $CP$ violation in the charm system
• Measurement of $CP$ observables in $B^{\pm }\to D^{(\ast )}{K}^{\pm }$ and $B^{\pm }\to D^{(\ast )}{\pi }^{\pm }$ decays using two-body $D$ final states
• Measurements of Absolute Branching Fractions of $D^0\to K_L^0\varphi$, $K_L^0\eta$, $K_L^0\omega$, and $K_L^0{\eta }^{\prime }$

Cited by in corpus (6)

• Measurement of the $CP$-even fraction of $D^0\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$
• Measurement of $D^0-{\overline{D}}^0$ mixing and search for $CP$ violation with $D^0\to K^{+}{\pi }^{-}$ decays
• Determination of the $CP$-even fraction of $D^0\to K_S^0{\pi }^{+}{\pi }^{-}{\pi }^0$
• First observation of quantum correlations in $e^{+}{e}^{-}\to XD\bar{D}$ and $C$-even constrained $D\bar{D}$ pairs
• A novel measurement of the strong-phase difference between $D^0\to K^{-}{\pi }^{+}$ and ${\bar{D}}^0\to K^{-}{\pi }^{+}$ decays using $C$-even and $C$-odd quantum-correlated $D\bar{D}$ pairs
• Measurement of the strong-phase difference between $D^0$ and $\overline{D^0}\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ in bins of phase space