Guo, ZH (reprint author), Hebei Normal Univ, Dept Phys, Shijiazhuang 050024, Peoples R China.
[Guo, Zhi-Hui] Hebei Normal Univ, Dept Phys, Shijiazhuang 050024, Peoples R China
In this article we study the impact of the lightest vector and scalar resonance multiplets in the pion and kaon decay constants up to next-to-leading order in the 1/N-C expansion, i.e., up to the one-loop level. The F-pi and F-K predictions obtained within the framework of resonance chiral theory are confronted with lattice simulation data. The vector loops (and the rho - pi pi coupling G(V) in particular) are found to play a crucial role in the determination of the chiral perturbation theory couplings L-4 and L-5 at next-to-leading order in 1/N-C. Puzzling, values of GV less than or similar to 40 MeV seem to be necessary to agree with current phenomenological results for L-4 and L-5. Conversely, a value of G(V) greater than or similar to 60 MeV compatible with standard rho - pi pi determinations turns these chiral couplings negative. However, in spite of the strong anti-correlation with L-4, the SU(3) chiral coupling F-0 remains stable all the time and stays within the range 78 similar to 86 MeV when G(V) is varied in a wide range, from 40 up to 70 MeV. Finally, we would like to remark that the leading order expressions used in this article for the eta - eta' mixing, mass splitting of the vector multiplet masses and the quark mass dependence of the rho(770) mass are found in reasonable agreement with the lattice data.