Observation of ${\Xi }^{-}$ Hyperon Transverse Polarization in $\psi (3686)\to {\Xi }^{-}{\bar{\Xi }}^{+}$

Abstract

Using a sample of $(448.1\pm 2.9)$ $\times 10^6$ $\psi (3686)$ decays collected with the BESIII detector at BEPCII, we report an observation of ${\Xi }^{-}$ transverse polarization with a significance of $7.3\sigma$ in the decay $\psi (3686)\to {\Xi }^{-}{\bar{\Xi }}^{+}$ (${\Xi }^{-}\to {\pi }^{-}\Lambda$, ${\bar{\Xi }}^{+}\to {\pi }^{+}\bar{\Lambda }$, $\Lambda \to p{\pi }^{-}$, $\bar{\Lambda }\to \bar{p}{\pi }^{+}$). The relative phase of the electric and magnetic form factors is determined to be $\Delta \Phi =(0.667\pm 0.111\pm 0.058)$ rad. This is the first measurement of the relative phase for a $\psi (3686)$ decay into a pair of ${\Xi }^{-}{\bar{\Xi }}^{+}$ hyperons. The ${\Xi }^{-}$ decay parameters (${\alpha }_{{\Xi }^{-}}$, ${\varphi }_{{\Xi }^{-}}$) and their conjugates (${\alpha }_{{\bar{\Xi }}^{+}}$, ${\varphi }_{{\bar{\Xi }}^{+}}$), the angular-distribution parameter ${\alpha }_{\psi }$, and the strong-phase difference ${\delta }_p-{\delta }_s$ for $\Lambda$-${\pi }^{-}$ scattering are measured to be consistent with previous BESIII results.

8 pages, 3 figures, consistent with paper published in Phys. Rev. D (Letter) 106, L091101 (2022)

References in corpus (8)

• Weak phases and CP-symmetry tests in sequential decays of entangled double-strange baryons
• ${\Sigma }^{+}$ and ${\bar{\Sigma }}^{-}$ polarization in the $J/\psi$ and $\psi (3686)$ decays
• Measurement of the cross section for $e^{+}{e}^{-}\to {\Xi }^{-}{\bar{\Xi }}^{+}$ and observation of an excited $\Xi$ baryon
• Measurement of cross-section for $e^{+}{e}^{-}\to {\Xi }^{-}{\bar{\Xi }}^{+}$ near threshold at BESIII
• Measurement of cross section for $e^{+}{e}^{-}\to {\Xi }^0{\bar{\Xi }}^0$ near threshold
• Measurement of the cross section for $e^{+}{e}^{-}\to \Lambda \bar{\Lambda }$ and evidence of the decay $\psi (3770)\to \Lambda \bar{\Lambda }$
• Measurement of $\Lambda$ baryon polarization in $e^{+}{e}^{-}\to \Lambda \bar{\Lambda }$ at $\sqrt{s}=3.773$ GeV
• Measurements of Baryon Pair Decays of ${\chi }_{cJ}$ Mesons

Cited by in corpus (16)

• Tests of $CP$ symmetry in the entangled ${\Xi }^0-{\bar{\Xi }}^0$ Pairs
• Strong and weak $CP$ tests in sequential decays of polarized ${\Sigma }^0$ hyperons
• First simultaneous measurement of ${\Xi }^0$ and ${\bar{\Xi }}^0$ asymmetry parameters in $\psi (3686)$ decay
• Study of $e^{+}{e}^{-}\to {\Omega }^{-}{\bar{\Omega }}^{+}$ at center-of-mass energies from 3.49 to 3.67 GeV
• Production and decay of polarized hyperon-antihyperon pairs
• Measurement of the cross section of $e^{+}{e}^{-}\to {\Xi }^{-}{\bar{\Xi }}^{+}$ at center-of-mass energies between 3.510 and 4.843 GeV
• Production and decay of hyperons in a transversely polarized electron-positron collider
• Prospects to study hyperon-nucleon interactions at BESIII
• Remarks on strong phase shifts in weak nonleptonic baryon 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
• Measurement of Born cross section of $e^{+}{e}^{-}\to {\Sigma }^0{\bar{\Sigma }}^0$ at $\sqrt{s}=3.50-4.95$ GeV
• Precise Measurement of Matter-Antimatter Asymmetry with Entangled Hyperon Antihyperon Pairs
• Isospin violating decays of vector charmonia
• Observation of Transverse Polarization and Determination of Psionic Form Factors of the $\Lambda$ Hyperon at $\sqrt{s}=3.773$ GeV
• Observation of $\Xi (1530{)}^0$ Polarization and Determination of Its Electric and Magnetic Moments in $\psi (3686)\to \Xi (1530{)}^0\bar{\Xi }(1530{)}^0$