Quark-mass dependence of the rho and sigma mesons from dispersion relations and chiral perturbation theory.
We use the one-loop chiral perturbation theory pipi-scattering amplitude and dispersion theory in the form of the inverse amplitude method to study the quark-mass dependence of the two lightest resonances of the strong interactions, the f(0)(600) (sigma) and the rho meson. As the main results, we find that the rhopipi coupling constant is almost quark mass independent and that the rho mass shows a smooth quark-mass dependence while that of the sigma shows a strong nonanalyticity. These findings are important for studies of the meson spectrum on the lattice.
Institut für Kernphysik (Theorie), Forschungzentrum Jülich, D-52425 Jülich, Germany.
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Hanhart
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Peláez
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Ríos