ON HEAVY-TO-HEAVY MESON TRANSITIONS IN THE EFFECTIVE QUARK-MODEL WITHCHIRAL-SYMMETRY

Heavy-quark effective theory (HQET) and chiral perturbation theory at the quark level (CHPT)(q), based on the extended Nambu-Jona-Lasinio mo del with linear realization of chiral U(3) x U(3) symmetry, are applie d to the calculation of form factors of heavy-to-heavy meson transitio ns. The application of such an effective quark model has led to the ap pearance of the additional factor 1/2 distinguishing the normalization of form factors given within QCD under the admission concerning the u nrenormalizability of HQET by strong low-energy interactions. One can explain this factor as a strong influence of heavy-antiquark degrees o f freedom, which die out in the infinite mass limit in constituent qua rk loops describing in such an effective quark model strong low-energy interactions at energies restricted by the spontaneous breaking of ch iral symmetry scale Lambda(chi) similar or equal to 1 GeV. This should evidence the renormalization of HQET within such an effective quark m odel by strong interactions at scales p < Lambda(chi) < M(Q), where M( Q) is the heavy Q-quark mass. Next-to-leading corrections in chiral an d heavy-quark mass expansion are computed. The violation of Luke's the orem within such an effective quark model is observed. The obtained re sults are confirmed within the effective quark model suggested by Bard een and Hill.