Gluonium nature of the sigma/f_0(600) from its coupling to KK

Abstract

We extract the K+K- couplings of the isoscalar scalar mesons sigma/f_0(600) and f_0(980) from pi pi to pi pi / K K scatterings and found: |g_{sigma K+K-}|/ |g_{sigma pi+pi-}|= 0.8 and |g_{f_0 K+K-}|/ |g_{f_0 pi+pi-}|= 1.7. These results, together with the tiny "direct" gamma gamma width of the sigma and its large hadronic width, are a strong indication for the gluonium/glueball nature of the sigma-meson, as predicted by QCD spectral sum rules (QSSR) + some low-energy theorems (LET), while some other assignements (pi pi molecule, tetraquark state and ordinary qq meson) do not satisfy simultaneously these requirements from the data. These properties suggest that the sigma can be a scalar meson associated to the U(1)V conformal anomaly like is the eta'-meson for the U(1)A anomaly.

One sentence and footnote added in section 3.1

References in corpus (14)

• The pion-pion scattering amplitude. III: Improving the analysis with forward dispersion relations and Roy equations
• Experimental status of the $\pi \pi$ isoscalar S wave at low energy: $f_0(600)$ pole and scattering length
• Two-photon decays of hadronic molecules
• Glueball nature of the sigma/f_0(600) from pi-pi and gamma-gamma scatterings
• Amplitude Analysis of High Statistics Results on $\gamma \gamma \to {\pi }^{+}{\pi }^{-}$ and the Two Photon Width of Isoscalar States
• Improved dispersion relations for γγ\to π^0π^0
• Two photons into π^0π^0
• Do the QCD sum rules support four-quark states?
• Location, correlation, radiation: where is the $\sigma$, what is its structure and what is its coupling to photons?
• A Dispersive Analysis on the $f_0(600)$ and $f_0(980)$ Resonances in $\gamma \gamma \to {\pi }^{+}{\pi }^{-},{\pi }^0{\pi }^0$ Processes
• Pole Mass, Width, and Propagators of Unstable Fermions
• The sigma -> gamma gamma Width from Nucleon Electromagnetic Polarizabilities
• Two-photon width and gluonic component of sigma/f_0(600)
• Arguments on the Light-mass Scalar Mesons and Concluding Remarks of the Meson Sessions

Cited by in corpus (1)

• Unitarity constraints on chiral perturbative amplitudes