Mass anomalous dimension in sextet QCD

TL;DR

This study investigates the mass anomalous dimension in sextet SU(3) gauge theory using the Schroedinger functional method, revealing a limited gamma_m value and suggesting the model's unsuitability for walking technicolor.

Contribution

The paper extends previous analyses by pushing the coupling range further and introduces a novel extrapolation method for near-conformal theories.

Findings

Gamma_m never exceeds 0.45

Results are consistent with an infrared fixed point

Model unlikely suitable for walking technicolor

Abstract

We extend our previous study of the SU(3) gauge theory with N_f=2 flavors of fermions in the sextet representation of color. Our tool is the Schroedinger functional method. By changing the lattice action, we push the bulk transition of the lattice theory to stronger couplings and thus reveal the beta function and the mass anomalous dimension gamma_m over a wider range of coupling, out to g^2 ~ 11. Our results are consistent with an infrared fixed point, but walking is not ruled out. Our main result is that gamma_m never exceeds 0.45, making the model unsuitable for walking technicolor. We use a novel method of extrapolation to the large-volume/continuum limit, tailored to near-conformal theories.