Pion properties in the 1/Nc-corrected NJL model

We investigate the effect of mesonic fluctuations on the pion propagator in the Nambu–Jona-Lasinio (NJL) model by explicitly taking into account 1/Nc-corrections. Because of the non-renormalizability of the model we have to regularize the meson loops with an independent cutoff parameter ΛM. Whereas for moderate values of ΛM the pion properties change only quantitatively we encounter strong instabilities for larger values of ΛM.