QCD string in light-light and heavy-light mesons - art. no. 014037

The spectra of light-light and heavy-light mesons are calculated within the framework of the QCD string model, which is derived from QCD in the Wilson loop approach. Special attention is paid to the proper string dynamics tha t allows us to reproduce the straight-line Regge trajectories with the inve rse slope being 2 pi sigma for light-light and twice as small for heavy-lig ht mesons. We use the model of the rotating QCD string with quarks at the e nds to calculate the masses of several light-light mesons lying on the lowe st Regge trajectories and compare them with the experimental data as well a s with the predictions of other models. The masses of several low-lying orb itally and radially excited heavy-light states in the D, D-s, B-s and B, me sons spectra are calculated in the einbein (auxiliary) field approach, whic h has proven to be rather accurate in various calculations for relativistic systems. The results for the spectra are compared with the experimental an d recent lattice data. It is demonstrated that an account of the proper str ing dynamics encoded in the so-called string correction to the interquark i nteraction leads to an extra negative contribution to the masses of orbital ly excited states that resolves the problem of the identification of the D( 2637) state recently claimed by the DELPHI Collaboration. For heavy-tight s ystem we extract the constants <(<Lambda>)over bar>, lambda (1), and lambda (2) used in heavy quark effective theory and find good agreement with the results of other approaches.