Traces of a fixed point: Unravelling the phase diagram at large Nf

TL;DR

This paper investigates the phase diagram of SU(3) Yang-Mills theory with twelve flavors, providing evidence for a conformal window and identifying a bulk transition to a chirally broken phase.

Contribution

It presents the first evidence of a bulk transition and Coulomb phase in SU(3) with twelve flavors, supporting the existence of a conformal window.

Findings

Evidence of a bulk transition towards a chirally broken phase

Existence of a Coulomb phase on the symmetric side of the transition

Positive sign of the beta function indicating conformality

Abstract

With a sufficiently high number of fundamental fermionic flavours present, Yang-Mills theory develops an infrared fixed point and becomes (quasi-)conformal in nature. The range of flavour numbers for which this occurs defines the conformal window, the lower limit of which has yet to be determined. We studied the phase diagram of SU(3) Yang-Mills theory with twelve flavours of staggered fermions. Here we present evidence for the occurrence of a bulk transition towards a chirally broken phase and the existence of a Coulomb phase on the symmetric side of this transition, using results from the measurements of the chiral condensate and spectrum, leading to the determination of a positive sign of the beta function. Assuming the validity of the Appelquist-Miransky-Yamawaki scenario, this implies the existence of a conformal window that comprises the theory under investigation.