English

Conformal Windows beyond Asymptotic Freedom

High Energy Physics - Theory 2021-11-17 v1 High Energy Physics - Phenomenology

Abstract

We study four-dimensional gauge theories coupled to fermions in the fundamental and meson-like scalars. All requisite beta functions are provided for general gauge group and fermion representation. In the regime where asymptotic freedom is absent, we determine all interacting fixed points using perturbation theory up to three loop in the gauge and two loop in the Yukawa and quartic couplings. We find that the conformal window of ultraviolet fixed points is narrowed-down by finite-NN corrections beyond the Veneziano limit. We also find a new infrared fixed point whose main features such as scaling exponents, UV-IR connecting trajectories, and phase diagram are provided. Both fixed points collide upon varying the number of fermion flavours NfN_{\rm f}, and conformality is lost through a saddle-node bifurcation. We further revisit the prospect for ultraviolet fixed points in the large NfN_{\rm f} limit where matter field fluctuations dominate. Unlike at weak coupling, we do not find clear evidence for new scaling solutions even in the presence of scalar and Yukawa couplings.

Keywords

Cite

@article{arxiv.2107.13020,
  title  = {Conformal Windows beyond Asymptotic Freedom},
  author = {Andrew D. Bond and Daniel F. Litim and Gustavo Medina Vazquez},
  journal= {arXiv preprint arXiv:2107.13020},
  year   = {2021}
}

Comments

20 pages, 10 figures

R2 v1 2026-06-24T04:34:32.378Z