Continuum QCD and light mesons

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The ladder-rainbow truncation of the set of Dyson-Schwinger equations is used to study light mesons. The parameters in the effective interaction are constrained by the chiral condensate and fπ; the current quark masses are fitted to mπand mₖ. The dressed quark propagators are in qualitative agreement with recent lattice-QCD results at low q² while having the correct perturbative behavior at large q². The resulting vector meson masses are within 5% of the experimental values. The obtained electromagnetic form factors and strong and electroweak coupling constants are also in good agreement with the data. At finite temperature, this truncation leads to a mean-field chiral phase transition. The spatial pion mass is almost constant below this transition, but rises with T close to and above Tc. The mass of its chiral partner, an idealized sigma meson, decreases with T until Tc, where it becomes degenerate with the pion.