The lowest resonance in QCD from low--energy data

Abstract

We show that a generalization of $su(2)$ Chiral Perturbation Theory, including a perturbative singlet scalar field, converges faster towards the physical value of sensible low--energy observables. The physical mass and width of the scalar particle are obtained through a simultaneous analysis of the pion radius and the gamma gamma -> pi^0 pi^0 cross-section. Both values are statistically consistent with the ones obtained by using Roy equations in pi-pi scattering. In addition we find indications that the photon-photon-singlet coupling is quite small.

pdfLatex 15 pages, 3 figures

References in corpus (7)

• Precise determination of the f0(600) and f0(980) pole parameters from a dispersive data analysis
• Revisiting γγ->π^+π^- at low energies
• Resonances from meson-meson scattering in U(3) CHPT
• No classical limit of quantum decay for broad states
• Large-Nc Properties of the rho and f0(600) Mesons from Unitary Resonance Chiral Dynamics
• Location, correlation, radiation: where is the $\sigma$, what is its structure and what is its coupling to photons?
• Chiral effective theory with a light scalar and lattice QCD

Cited by in corpus (3)

• One-loop $\gamma \gamma \to W_L^{+}{W}_L^{-}$ and $\gamma \gamma \to Z_L{Z}_L$ from the Electroweak Chiral Lagrangian with a light Higgs-like scalar
• The reactions $\pi \pi \to \pi \pi$ and $\gamma \gamma \to \pi \pi$ in $\chi$PT with an isosinglet scalar resonance
• Insights into $Q^2{\bar{Q}}^2$ states from an effective perspective