QCD sum rules and radial excitaions of light pseudoscalar and scalar mesons

Abstract

The calculations of masses and decay constants of the radial excitations of light pseudoscalar and scalar mesons within QCD sum rules method are briefly reviewed. The predictions are based on the $1/N_c$-supported model spectra, which consist of infinite number of infinitely narrow resonances, and on the assumption that the ground states of light scalar mesons may be considered as the $\bar{q}q$-bound states. The results of the studies are compared with the existing experimental data and with the predictions of other theoretical approaches.