Strong and weak $CP$ tests in sequential decays of polarized ${\Sigma }^0$ hyperons

Abstract

The $J/\psi ,\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0$ processes and subsequent decays are studied using the world's largest $J/\psi$ and $\psi (3686)$ data samples collected with the BESIII detector. The strong-$CP$ symmetry is tested in the decays of the ${\Sigma }^0$ hyperons for the first time by measuring the decay parameters, ${\alpha }_{{\Sigma }^0}=-0.0017\pm 0.0021\pm 0.0018$ and ${\bar{\alpha }}_{{\Sigma }^0}=0.0021\pm 0.0020\pm 0.0022$. The weak-$CP$ test is performed in the subsequent decays of their daughter particles $\Lambda$ and $\bar{\Lambda }$. Also for the first time, the transverse polarizations of the ${\Sigma }^0$ hyperons in $J/\psi$ and $\psi (3686)$ decays are observed with opposite directions, and the ratios between the S-wave and D-wave contributions of the $J/\psi ,\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0$ decays are obtained. These results are crucial to understand the decay dynamics of the charmonium states and the production mechanism of the ${\Sigma }^0-{\bar{\Sigma }}^0$ pairs.

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• Design and Construction of the BESIII Detector
• Coherent Exclusive Exponentiation For Precision Monte Carlo Calculations
• Observation of Large CP Violation in the Neutral B Meson System
• Measurement of the permanent electric dipole moment of the neutron
• Future Physics Programme of BESIII
• Observation of CP violation in the B^0 meson system
• Observation of $CP$ violation in charm decays
• Polarization and Entanglement in Baryon-Antibaryon Pair Production in Electron-Positron Annihilation
• Method for detector description transformation to Unity and application in BESIII
• Number of $J/\psi$ events at BESIII
• Hadronic structure functions in the $e^{+}{e}^{-}\to \bar{\Lambda }\Lambda$ reaction
• 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
• Prospects for rare and forbidden hyperon decays at BESIII
• ${\Sigma }^{+}$ and ${\bar{\Sigma }}^{-}$ polarization in the $J/\psi$ and $\psi (3686)$ decays
• Study of $J/\psi$ and $\psi (3686)$ decay to $\Lambda \bar{\Lambda }$ and ${\Sigma }^0{\bar{\Sigma }}^0$ final states
• Determination of the number of $\psi (3686)$ events taken at BESIII
• Spin asymmetries and correlations in lambda-pair production through the radiative return method
• General analysis of polarization phenomena in $e^{+}+e^{-}\to N+\bar{N}$ for axial parametrization of two--photon exchange
• Tests of $CP$ symmetry in the entangled ${\Xi }^0-{\bar{\Xi }}^0$ Pairs
• Observation of ${\Xi }^{-}$ Hyperon Transverse Polarization in $\psi (3686)\to {\Xi }^{-}{\bar{\Xi }}^{+}$
• Model independent determination of the spin of the ${\Omega }^{-}$ and its polarization alignment in $\psi (3686)\to {\Omega }^{-}{\bar{\Omega }}^{+}$
• Measurement of CP violation in $B^0\to \psi (\to {\ell }^{+}{\ell }^{-})K_S^0(\to {\pi }^{+}{\pi }^{-})$ decays
• First simultaneous measurement of ${\Xi }^0$ and ${\bar{\Xi }}^0$ asymmetry parameters in $\psi (3686)$ decay
• Measurement of $\Lambda$ transverse polarization in $e^{+}{e}^{-}$ collisions at $\sqrt{s}=3.68-3.71$ GeV
• Constraining P and CP violation in the main decay of the neutral Sigma hyperon
• Polarization difference between hyperons and anti-hyperons induced by external magnetic field
• Sequential hyperon decays in the reaction $e^{+}{e}^{-}\to {\Sigma }^0{\bar{\Sigma }}^0$
• Observation of the decay ${\chi }_{cJ}\to {\Omega }^{-}{\bar{\Omega }}^{+}$
• The effective radius for production of baryon-antibaryon pairs from $\psi$ decays
• Measurements of the absolute branching fractions of ${\Omega }^{-}$ decays and test of the $\Delta I=1/2$ rule
• Search for $\text{CP}$ violation in the phase space of $D^0\to K_S^0{K}^{\pm }{\pi }^{\mp }$ decays with the energy test

Cited by in corpus (7)

• Stringent test of $CP$ symmetry in ${\Sigma }^{+}$ hyperon decays
• The electromagnetic form factors and spin polarization of ${\Lambda }_c^{+}$ in the process $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$
• Tests of CP symmetry in entangled hyperon anti-hyperon pairs at BESIII
• Observation of Transverse Polarization and Determination of Psionic Form Factors of the $\Lambda$ Hyperon at $\sqrt{s}=3.773$ GeV
• Observation of the decay $\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0\omega$
• Observation of $\Xi (1530{)}^0$ Polarization and Determination of Its Electric and Magnetic Moments in $\psi (3686)\to \Xi (1530{)}^0\bar{\Xi }(1530{)}^0$
• Observation of $\bar{\Lambda }p\to K^{+}{\pi }^{+}{\pi }^{-}{\pi }^0$ and $\bar{\Lambda }p\to K^{+}{\pi }^{+}{\pi }^{-}2{\pi }^0$