Meson properties in the 1/Nc-corrected NJL model Original Research Article

Properties of mesons are investigated within the Nambu–Jona-Lasinio model. We include meson-loop corrections, which are generated via a systematic 1/Nc-expansion in next-to-leading order. We show that our scheme is consistent with chiral symmetry, in particular with the Goldstone theorem and the Gell-Mann–Oakes–Renner relation. The numerical part focuses on the pion and the ρ-meson sector. For the latter the 1/Nc-corrections are crucial in order to include the dominant ρ→ππ-decay channel, while the leading-order approximation only contains unphysical View the MathML source-decay channels. We show that a satisfactory description of the pion electromagnetic form factor can be obtained. Similarities and differences to hadronic models are discussed.