SU(2) gauge theory with $N_f=24$ quarks at non-zero mass

TL;DR

This paper investigates the behavior of SU(2) gauge theory with 24 quarks at non-zero mass, analyzing its spectrum, coupling evolution, and decoupling phenomena to understand its phase structure and dynamics.

Contribution

It provides the first detailed study of the mass spectrum and coupling evolution of SU(2) with 24 quarks, highlighting quark decoupling and scaling laws.

Findings

Quarks decouple at non-zero mass, leading to pure gauge behavior.

Scaling laws for meson masses and string tension are established.

Coupling constant evolution shows clear decoupling transition.

Abstract

We study SU(2) gauge field theory with $N_f=24$ quarks. The theory is asymptotically non-free and, at vanishing quark mass, governed by a Gaussian fixed point at long distances. On the other hand, at non-zero quark mass the quarks are expected to decouple at long distances and the system behaves like confining pure gauge SU(2) theory. We study the mass spectrum of the theory as the quark mass is varied and obtain scaling laws for meson masses and string tension. We also measure the evolution of the coupling constant at non-zero quark mass with gradient flow method. We observe unambiguously the decoupling of the quarks with the associated change of evolution of the coupling constant.