Determining the conformal window: SU(2) gauge theory with N f = 4, 6 and 10 fermion flavours

2011/11/30 by Tuomas Karavirta, Jarno Rantaharju, Kari Rummukainen +1
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Conformal map #Coupling (piping) #Fermion #Fixed point #Gauge (firearms) #Gauge theory #Geometry #Infrared #Infrared fixed point #Lattice (music) #Materials science #Mathematical analysis #Mathematical physics #Mathematics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Renormalization group #Theoretical physics #hep-lat

paper · pdf · doi:10.1007/jhep05(2012)003

published as JHEP 1205:003,2012 · 22 pages, 12 figures. Proof reading

openalex publication_date 2012/05/01 · arxiv created 2012/06/06 · arxiv updated 2015/03/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We study the evolution of the coupling in SU(2) gauge field theory with N_f=4, 6 and 10 fundamental fermion flavours on the lattice. These values are chosen close to the expected edges of the conformal window, where the theory possesses an infrared fixed point. We use improved Wilson-clover action, and measure the coupling in the Schrödinger functional scheme. At four flavours we observe that the couping grows towards the infrared, implying QCD-like behaviour, whereas at ten flavours the results are compatible with a Banks-Zaks type infrared fixed point. The six flavour case remains inconclusive: the evolution of the coupling is seen to become slower at the infrared, but the accuracy of the results falls short from fully resolving the fate of the coupling. We also measure the mass anomalous dimension for the N_f=6 case.

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