ΔS=0 Effective Weak Chiral Lagrangian from the Instanton Vacuum

Original · EN

We investigate the ΔS=0 effective chiral Lagrangian from the instanton vacuum. Based on the ΔS=0 effective weak Hamiltonian from the operator product expansion and renormalization group equations, we derive the strangeness-conserving effective weak chiral Lagrangian from the instanton vacuum to order O(p²) and the next-to-leading order in the 1/Nc expansion at the quark level. We find that the quark condensate and a dynamical term which arise from the QCD and electroweak penguin operators appear in the next-to-leading order in the 1/Nc expansion for the ΔS =0 effective weak chiral Lagrangian, while they are in the leading order terms in the ΔS = 1 case. Three different types of the form factors are employed and we find that the dependence on the different choices of the form factor is rather insensitive. The low-energy constants of the Gasser-Leutwyler type are determined and discussed in the chiral limit.