# M.S. Physics Thesis Talk: Andrew Freeman - "Dilaton Chiral Perturbation Theory at the Next-to-Leading Order"

## Overview

Abstract: It has been observed that a favor-singlet scalar meson that is approximately as light as the pion exists in numerical simulations of the SU(3) gauge theory with N_f = 8 fermions in the fundamental representation. Confnement and chiral symmetry breaking still take place in this theory, but the beta function is small enough to where this light scalar could be the Nambu-Goldstone boson associated with the breaking of dilatation symmetry. In order to account for the presence of this light scalar meson, a low-energy efective action that includes pions and this “dilatonic” meson was developed in Ref. [11]. This efective theory has been given the name dilaton chiral perturbation theory (dChPT). We further explore the predictive power of dChPT by calculating the next-to-leading order contributions for the pion decay constant F_π and the pion mass squared m^2_π.