Near-conformal dynamics in a chirally broken system

Appelquist, Thomas; Brower, Richard C.; Cushman, Kimmy K.; Fleming, George T.; Gasbarro, Andrew D.; Hasenfratz, Anna; Jin, Xiao-Yong; Neil, Ethan T.; Osborn, James C.; Rebbi, Claudio; Rinaldi, Enrico; Schaich, David; Vranas, Pavlos; Witzel, Oliver (2021). Near-conformal dynamics in a chirally broken system. Physical review. D - particles, fields, gravitation, and cosmology, 103(1), 014504. American Physical Society 10.1103/PhysRevD.103.014504

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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 phenom- enological 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) suggesting that Nf = 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 0þþ isosinglet scalar.

Item Type:

Journal Article (Original Article)


10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Institute of Theoretical Physics

UniBE Contributor:

Gasbarro, Andrew David and Schaich, David Alexander


500 Science > 530 Physics




American Physical Society




Esther Fiechter

Date Deposited:

12 Feb 2021 12:18

Last Modified:

12 Feb 2021 12:18

Publisher DOI:


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