Measurement of CP Asymmetry Parameters and Polarization Correlations in ${\Omega }^{-}{\bar{\Omega }}^{+}$ Pairs

Abstract

Using $(2.71\pm 0.01)\times 10^9$ $\psi (3686)$ events collected with the BESIII detector, a joint full angular distribution analysis is carried out for the process $\psi (3686)\to {\Omega }^{-}(\to \Lambda K^{-}){\bar{\Omega }}^{+}(\to \bar{\Lambda }{K}^{+})$. The first simultaneous measurement of the weak decay parameters ${\varphi }_{{\Omega }^{-}}$ and ${\varphi }_{{\bar{\Omega }}^{+}}$ for ${\Omega }^{-}\to K^{-}\Lambda$ and ${\bar{\Omega }}^{+}\to K^{+}\bar{\Lambda }$ is performed, yielding the first result for the CP-sensitive observable, ${\varphi }_{\mathrm{CP}}=(-0.004\pm 0.055\pm 0.017)\text{rad}$, where the first and second uncertainties are statistical and systematic, respectively. This further enables the extraction of the weak and strong phase differences between the $P$- and $D$-wave amplitudes: $({\xi }_D-{\xi }_P)=(-0.15\pm 2.25\pm 0.69)\text{rad}$ and $({\delta }_D-{\delta }_P)=(-0.97\pm 0.88\pm 0.34)\text{rad}$. Additionally, the polarization correlations between ${\Omega }^{-}$ and ${\bar{\Omega }}^{+}$ are measured.