First Measurements of Timelike Form Factors of the Hyperons, Lambda0, Sigma0, Sigma+, Xi0, Xi-, and Omega-, and Evidence of Diquark Correlations

Abstract

Using 805 pb^-1 of e+e- annihilation data taken with the CLEO-c detector at psi(3770), sqrt{s}=3770 MeV, we report the first measurements of the electromagnetic form factors of the Lambda0, Sigma0, Sigma+, Xi0, Xi-, and Omega- hyperons for the large timelike momentum transfer of |Q^2|=14.2 GeV^2. The form factors for the different hyperons are found to vary by nearly a factor two. It is found that |G_M(Lambda0)|=1.66(24) x |G_M(Sigma0)|. The Lambda0 and Sigma0 hyperons have the same uds quark content, but differ in their isospin, and therefore the spin of the $ud$ quark pair. It is suggested that the spatial correlation implied by the singlet spin--isospin configuration in the Lambda0 is an example of strong diquark correlations in the Lambda0, as anticipated by Jaffe and Wilczek. Improved measurements of the branching fractions of psi(2S) -> p pbar and hyperon--antihyperon pairs are also reported.

5 pages, 4 figures

Cited by in corpus (22)

• Baryons as relativistic three-quark bound states
• ${\Sigma }^{+}$ and ${\bar{\Sigma }}^{-}$ polarization in the $J/\psi$ and $\psi (3686)$ decays
• Hyperon Form Factors & Diquark Correlations
• The electromagnetic form factors of the $\Lambda$ in the timelike region
• Hyperon electromagnetic form factors in the timelike region
• Measurement of $\Lambda$ baryon polarization in $e^{+}{e}^{-}\to \Lambda \bar{\Lambda }$ at $\sqrt{s}=3.773$ GeV
• Electromagnetic form factors of the ${\Omega }^{-}$ baryon in the spacelike and timelike regions
• The $\Sigma$ and $\Xi$ electromagnetic form factors in the extended vector meson dominance model
• Production and decay of polarized hyperon-antihyperon pairs
• Electromagnetic $|G_E/G_M|$ ratios of hyperons at large timelike $q^2$
• Measurement of $\Lambda$ transverse polarization in $e^{+}{e}^{-}$ collisions at $\sqrt{s}=3.68-3.71$ GeV
• Dispersion-theoretical analysis of the electromagnetic form factors of the $\Lambda$ hyperon
• Understanding oscillating features of the timelike nucleon electromagnetic form factors within the extending vector meson dominance model
• $\Lambda \bar{\Lambda }$ final-state interaction in the reactions $e^{+}{e}^{-}\to \varphi \Lambda \bar{\Lambda }$ and $e^{+}{e}^{-}\to \eta \Lambda \bar{\Lambda }$
• The cross section of the process $e^{+}{e}^{-}\to \Lambda \bar{\Lambda }$ in the vicinity of charmonium $\psi (3770)$ including three-gluon and $D$-meson loop contributions
• Symmetry analysis of charmonium two-body decay
• Measurement of ${\Sigma }^{+}$ transverse polarization in $e^{+}{e}^{-}$ collisions at $\sqrt{s}=3.68-3.71$ GeV
• Search for Charmonium(-like) states decaying into the ${\Omega }^{-}{\bar{\Omega }}^{+}$ final states
• Chiral-odd generalized parton distributions for the low-lying octet baryons
• Observation of Transverse Polarization and Determination of Psionic Form Factors of the $\Lambda$ Hyperon at $\sqrt{s}=3.773$ GeV
• Time-like electromagnetic form factors of $\Lambda ,\Sigma$ and ${\Xi }^{+}$ in a light-front quark model
• Observation of $\Xi (1530{)}^0$ Polarization and Determination of Its Electric and Magnetic Moments in $\psi (3686)\to \Xi (1530{)}^0\bar{\Xi }(1530{)}^0$