Low energy spectra in many flavor QCD with Nf=12 and 16

TL;DR

This study investigates the low-energy spectra of SU(3) gauge theories with 12 and 16 flavors, providing evidence for conformal behavior at Nf=12 and estimating the mass anomalous dimension, contributing to understanding potential new physics models.

Contribution

The paper presents lattice QCD results for Nf=12 and 16, analyzing spectra and finite size scaling to explore conformal dynamics and estimate the mass anomalous dimension.

Findings

Data for Nf=12 supports conformal scenario

Mass anomalous dimension estimated as 0.4-0.5

Updated results for Nf=16 included

Abstract

We present our result of the many-flavor QCD. Information of the phase structure of many-flavor SU(3) gauge theory is of great interest, since the gauge theories with the walking behavior near the infrared fixed point are candidates of new physics for the origin of the dynamical electroweak symmetry breaking. We study the SU(3) gauge theories with 12 and 16 fundamental fermions. Utilizing the HISQ type action which is useful to study the continuum physics, we analyze the lattice data of the mass and the decay constant of the pseudoscalar meson and the mass of the vector meson as well at several values of lattice spacing and fermion mass. The finite size scaling test in the conformal hypothesis is also performed. Our data is consistent with the conformal scenario for Nf=12. We obtain the mass anomalous dimension $\gamma_m \sim 0.4-0.5$. An update of $N_f=16$ study is also shown.