Lightest Scalar Resonances and the Dynamics of the γγ\toππReactions

Abstract

The high-statistics Belle data on the γγ\toπ^+π^- and γγ\toπ^0π^0 reactions have been jointly analyzed. The main dynamical mechanisms of these reactions for energies below 1.5 GeV have been revealed. It has been shown that the direct coupling constants of the σ(600) and f_0(980) resonances with a γγpair are small and that the σ(600)\toγγand f_0(980)\toγγdecays are four-quark transitions due primarily to π^+π^- and K^+K^- loop mechanisms, respectively. The role of the chiral shielding of the σ(600) resonance is emphasized. The widths of the f_0(980)\toγγand σ(600)\toγγdecays averaged over the resonance mass distributions, as well as the width of the f_2(1270)\toγγdecay, are estimated as (Γ_{f_0\toγγ})_{ππ}\approx 0.19 keV, (Γ_{σ\toγγ})_{ππ}\approx 0.45 keV, and Γ_{f_2\toγγ}(m^2_{f_2})\approx 3.8$ keV.

arXiv comment6 pages, 3 figures

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Cited by in corpus (7)

• Comprehensive Amplitude Analysis of $\gamma \gamma \to {\pi }^{+}{\pi }^{-},{\pi }^0{\pi }^0$ and $\overline{K}K$ below 1.5 GeV
• Two photon couplings of the lightest isoscalars from BELLE data
• Nature of the a_0(980) Meson in the Light of Photon-Photon Collisions
• Gauged linear sigma model and pion-pion scattering
• ${\pi }^{+}{\pi }^{-}$ and ${\pi }^0{\pi }^0$ pair production in photon-photon and in ultraperipheral ultrarelativistic heavy ion collisions
• Exclusive production of large invariant mass pion pairs in ultraperipheral ultrarelativistic heavy ion collisions
• Nature of light scalars through photon-photon collisions