August 28, 2016 to September 4, 2016
Europe/Athens timezone

Chiral-Scale Perturbation Theory and the Renormalization Group

Sep 1, 2016, 3:00 PM
Aristotelis II (Makedonia Palace)

Aristotelis II

Makedonia Palace

Section B: Light Quarks Section B


Lewis Tunstall (University of Bern)


Three-flavor chiral perturbation theory with $t,b,c$ quarks decoupled tests the infrared limit of three-flavor QCD. The standard theory $\chi$PT$_3$ (before being unitarized) assumes that there is no infrared fixed point $\alpha_{\mathrm{IR}}$. If $\alpha_{\mathrm{IR}}$ exists, we get chiral-scale perturbation theory $\chi$PT$_\sigma$ about a scale-invariant theory where the quark condensate is also a scale condensate with nine Nambu-Goldstone (NG) bosons: a massless $0^{++}$ dilaton $\sigma$ ($f_0(500)$ in the real world) as well as $\pi,K,\eta$. The effective Lagrangian for $\chi$PT$_\sigma$ is the standard one modified by $\sigma$-dependent terms and factors required to give the correct scaling dimensions, and can be systematically extended to include higher-order and electroweak corrections. The most important result is a neat explanation of the $\Delta I=1/2$ puzzle for kaon decays; we propose to test it on the lattice via $K\to \pi$ with both on shell.

Primary author

Lewis Tunstall (University of Bern)


Dr Rod Crewther (The University of Adelaide)

Presentation materials