On heavy-to-heavy meson transitions in the effective quark model with chiral symmetry

Summary. — Heavy-quark effective theory (HQET) and chiral perturbation theory at the quark level (CHPT)q , based on the extended Nambu-Jona-Lasinio model with linear realization of chiral U (3) 3 U( 3 ) symmetry, are applied to the calculation of form factors of heavy-to-heavy meson transitions. The application of such an effective quark model has led to the appearance of the additional factor 1O2 distinguishing the normalization of form factors given within QCD under the admission concerning the unrenormalizability of HQET by strong low-energy interactions. One can explain this factor as a strong influence of heavy-antiquark degrees of freedom, which die out in the infinite mass limit in constituent quark loops describing in such an effective quark model strong low-energy interactions at energies restricted by the spontaneous breaking of chiral symmetry scale L xC 1 GeV. This should evidence the renormalization of HQET within such an effective quark model by strong interactions at scales pE L xE MQ , where MQ is the heavy Q-quark mass. Next-to-leading corrections in chiral and heavy-quark mass expansion are computed. The violation of Luke8s theorem within such an effective quark model is observed. The obtained results are confirmed within the effective quark model suggested by Bardeen and Hill. PACS 12.90 ‐ Miscellaneous theoretical ideas and models. PACS 12.39.Ba ‐ Bag model. PCAS 13.40.Ks ‐ Electromagnetic corrections to strong- and weak-interaction processes.