Heavy-light mesons in QCD

This talk smarizes the study of the dynamics of the heavy-light open charm and beauty mesons obtained in [1] using QCD spectral sum rules (QSSR) and motivated by the recent experimental discovery of the DsJ(2317) and DsJ(2457) mesons. The important rôle of the chiral condensate in the mass-splittings between the scalar- pseudoscalar mesons is emphasized. The emerging value of the running charm quark mass for reproducing the well-known D(0−) and Ds(0−) masses is: , which confirms previous estimates from this channel [2]. Using this value, the sum rules give: MDs(0+)≃(2297±113)MeV, and a small SU(3) breaking: MDs(0+)−MD(0+)≈25MeV. Extending the analysis to the B-system; one finds: MB(0+)−MB(0−)≃(422±196)MeV≃MDs(0+)−MDs(0−). Assuming an approximate (heavy and light) flavour and spin symmetries of the mass-splittings as indicated by the previous results, one also deduces: . Finally, one also gets: fD(0+)≃(217±25)MeV much bigger than ƒπ=130.6 MeV, suggesting a large violation of the scaling, while the size of the SU(3) breaking ratio fDs(0+)/fD(0+)≃0.93±0.02 is opposite to the one of the 0− channel of about 1.14.