Dilaton chiral perturbation theory and applications

TL;DR

Dilaton chiral perturbation theory (dChPT) is an effective framework for describing light scalar and pseudoscalar particles in near-conformal, confining theories, with applications to lattice data and systematic expansion in relevant parameters.

Contribution

This paper reviews dChPT, highlighting its unique large-mass regime with approximate hyperscaling and its systematic approach to low-energy phenomena near the conformal window.

Findings

dChPT successfully describes lattice data for near-conformal theories.

The theory accounts for both pions and a light scalar as Nambu-Goldstone bosons.

It demonstrates a large-mass regime with approximate hyperscaling.

Abstract

We review dilaton chiral perturbation theory (dChPT), the effective low-energy theory for the light sector of near-conformal, confining theories. dChPT provides a systematic expansion in both the fermion mass and the distance to the conformal window. It accounts for the pions and the light scalar, the approximate Nambu-Goldstone bosons for chiral and scale symmetry, respectively. A unique feature of dChPT is the existence of a large-mass regime in which the theory exhibits approximate hyperscaling, while the expansion nevertheless remains systematic. We discuss applications to lattice data, presenting successes as well as directions for future work.