Some implications of meson dominance in weak interactions

Abstract

The hypothesis is scrutinized that the weak interaction of hadronic systems at low energies is dominated by the coupling of the pseudoscalar, vector, and axial-vector mesons to the weak gauge bosons. The strength of the weak coupling of the rho(770) meson is uniquely determined by vector-meson dominance in electromagnetic interactions; flavor and chiral symmetry breaking effects modify the coupling of other vector mesons and axial-vector mesons. Many decay rates are calculated and compared to experimental data and partly to predictions of other models. A parameter-free description of the decay K^+ --> pi^+ e^+e^- is obtained. Predictions for several not yet observed decay rates and reaction cross sections are presented. The relation between the conserved vector current hypothesis and meson dominance is clarified. Phenomenological success of the meson dominance suggests that in some calculations based on the standard model the weak quark-antiquark annihilation and creation diagrams may be more important than anticipated so far. The processes are identified where the meson dominance fails, implying that they are governed, on the quark level, by some other standard model diagrams.