Speaker: Lewis C. Tunstall (University of Bern)
Title: Chiral-scale Perturbation Theory and the Delta I = 1/2 rule in K-decays
Abstract: Chiral-scale perturbation theory (ChPT_sigma) has been proposed as an alternative to chiral SU(3) x SU(3) perturbation theory which explains the Delta I = 1/2 rule for kaon decays. It is based on a low-energy expansion about an infrared fixed point in three-flavor QCD. In ChPT_sigma, quark condensation at the fixed point induces nine Nambu-Goldstone bosons: pi, K, eta and a QCD dilaton sigma which we identify with the f0(500) resonance. In this talk, I discuss the construction of the ChPT_sigma Lagrangian and its implications for meson phenomenology at low-energies. To test ChPT_sigma for kaon decays, I revive a 1985 proposal for lattice methods to be applied to K --> pi on-shell.