English

Near-conformal dynamics in a chirally broken system

High Energy Physics - Phenomenology 2021-01-13 v2 High Energy Physics - Lattice

Abstract

Composite Higgs models must exhibit very different dynamics from quantum chromodynamics (QCD) regardless whether they describe the Higgs boson as a dilatonlike state or a pseudo-Nambu-Goldstone boson. Large separation of scales and large anomalous dimensions are frequently desired by phenomenological models. Mass-split systems are well-suited for composite Higgs models because they are governed by a conformal fixed point in the ultraviolet but are chirally broken in the infrared. In this work we use lattice field theory calculations with domain wall fermions to investigate a system with four light and six heavy flavors. We demonstrate how a nearby conformal fixed point affects the properties of the four light flavors that exhibit chiral symmetry breaking in the infrared. Specifically we describe hyperscaling of dimensionful physical quantities and determine the corresponding anomalous mass dimension. We obtain ym=1+γ=1.47(5)y_m=1+\gamma^*= 1.47(5) suggesting that Nf=10N_f=10 lies inside the conformal window. Comparing the low energy spectrum to predictions of dilaton chiral perturbation theory, we observe excellent agreement which supports the expectation that the 4+6 mass-split system exhibits near-conformal dynamics with a relatively light 0++0^{++} isosinglet scalar.

Keywords

Cite

@article{arxiv.2007.01810,
  title  = {Near-conformal dynamics in a chirally broken system},
  author = {Thomas Appelquist and Richard C. Brower and Kimmy K. Cushman and George T. Fleming and Andrew D. Gasbarro and Anna Hasenfratz and Xiao-Yong Jin and Ethan T. Neil and James C. Osborn and Claudio Rebbi and Enrico Rinaldi and David Schaich and Pavlos Vranas and Oliver Witzel},
  journal= {arXiv preprint arXiv:2007.01810},
  year   = {2021}
}

Comments

7 pages, 5 figures, v2 version published in Phys. Rev. D

R2 v1 2026-06-23T16:50:12.291Z