Tests of $CP$ symmetry in the entangled ${\Xi }^0-{\bar{\Xi }}^0$ Pairs

Abstract

The $J/\psi \to {\Xi }^0{\bar{\Xi }}^0$ process and subsequent decays are investigated using $(10087\pm 44)\times 10^6$ $J/\psi$ events collected at the BESIII experiment. The decay parameters of ${\Xi }^0$ and ${\bar{\Xi }}^0$ are measured with greatly improved precision over previous measurements to be ${\alpha }_{\Xi }=-0.3750\pm 0.0034\pm 0.0016$, ${\bar{\alpha }}_{\Xi }=0.3790\pm 0.0034\pm 0.0021$, ${\varphi }_{\Xi }=0.0051\pm 0.0096\pm 0.0018$~rad, ${\bar{\varphi }}_{\Xi }=-0.0053\pm 0.0097\pm 0.0019$~rad, where the first and the second uncertainties are statistical and systematic, respectively. From these measurements, precise $CP$ symmetry tests in ${\Xi }^0$ decay are performed, and $A_{CP}^{\Xi }=(-5.4\pm 6.5\pm 3.1)\times 10^{-3}$ and $\Delta {\varphi }_{CP}^{\Xi }=(-0.1\pm 6.9\pm 0.9)\times 10^{-3}$~rad are consistent with $CP$ conservation. The sequential decay also enables a separation of weak and strong phase differences, which are found for the first time to be ${\xi }_P-{\xi }_S=(0.0\pm 1.7\pm 0.2)\times 10^{-2}$~rad and ${\delta }_P-{\delta }_S=(-1.3\pm 1.7\pm 0.4)\times 10^{-2}$~rad, respectively. In addition, we measure the $\Lambda$ decay parameters and test $CP$ symmetry in $\Lambda$ decays.

References in corpus (12)

• Future Physics Programme of BESIII
• Matter and Antimatter in the Universe
• Observation of $CP$ violation in charm decays
• Method for detector description transformation to Unity and application in BESIII
• Number of $J/\psi$ events at BESIII
• Weak phases and CP-symmetry tests in sequential decays of entangled double-strange baryons
• Precise Measurements of Decay Parameters and $CP$ Asymmetry with Entangled $\Lambda -\bar{\Lambda }$ Pairs
• ${\Sigma }^{+}$ and ${\bar{\Sigma }}^{-}$ polarization in the $J/\psi$ and $\psi (3686)$ decays
• Spin asymmetries and correlations in lambda-pair production through the radiative return method
• Study of CP violation in hyperon decays at Super Charm-Tau Factories with a polarized electron beam
• Observation of ${\Xi }^{-}$ Hyperon Transverse Polarization in $\psi (3686)\to {\Xi }^{-}{\bar{\Xi }}^{+}$
• First simultaneous measurement of ${\Xi }^0$ and ${\bar{\Xi }}^0$ asymmetry parameters in $\psi (3686)$ decay

Cited by in corpus (11)

• Strong and weak $CP$ tests in sequential decays of polarized ${\Sigma }^0$ hyperons
• First Measurement of the Decay Asymmetry in the pure W-boson-exchange Decay ${\Lambda }_c^{+}\to {\Xi }^0{K}^{+}$
• Probing hyperon electric dipole moments with a full angular analysis
• Prospects to study hyperon-nucleon interactions at BESIII
• The electromagnetic form factors and spin polarization of ${\Lambda }_c^{+}$ in the process $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$
• Remarks on strong phase shifts in weak nonleptonic baryon decays
• Measurement of Born cross section of $e^{+}{e}^{-}\to {\Sigma }^0{\bar{\Sigma }}^0$ at $\sqrt{s}=3.50-4.95$ GeV
• Tests of CP symmetry in entangled hyperon anti-hyperon pairs at BESIII
• Unraveling the structure of $\Lambda$ hyperons with polarized $\Lambda \bar{\Lambda }$ pairs
• Precise Measurement of Matter-Antimatter Asymmetry with Entangled Hyperon Antihyperon Pairs
• Observation of $\bar{\Lambda }p\to K^{+}{\pi }^{+}{\pi }^{-}{\pi }^0$ and $\bar{\Lambda }p\to K^{+}{\pi }^{+}{\pi }^{-}2{\pi }^0$