Extending chiral perturbation theory with an isosinglet scalar

Hansen, Martin; Langæble, Kasper; Sannino, Francesco

doi:10.1103/physrevd.95.036005

Cited by 65 publications

(69 citation statements)

References 70 publications

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“…While looking for explanations, so far without results, it is natural to raise the question if the quality of the data set can really differentiate between dilaton and σ-model scenarios. The more robust general test yielded an exponent y close to y = 2 which perhaps could be accommodated in some generalized effective action of the σ-model with added terms and with loop corrections [31,32]. This is illustrated next with the conventional fitting procedure in chiral perturbation theory.…”

Section: Tests Of the Asymptotic Dilaton Potential V(χ) ∼ χ Pmentioning

confidence: 87%

The twelve-flavor β-function and dilaton tests of the sextet scalar

et al. 2018

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Abstract. We discuss near-conformal gauge theories beyond the standard model (BSM) where interesting results on the twelve-flavor β-function of massless fermions in the fundamental representation of the SU(3) color gauge group and dilaton tests of the light scalar with two massless fermions in the two-index symmetric tensor (sextet) representation can be viewed as parts of the same BSM paradigm under investigation. The clear trend in the decreasing size of β-functions at fixed renormalized gauge coupling is interpreted as a first indicator how the conformal window (CW) is approached in correlation with emergent near-conformal light scalars. BSM model building close to the CW will be influenced by differing expectations on the properties of the emergent light 0 ++ scalar either as a σ-particle of chiral symmetry breaking (χS B), or as a dilaton of scale symmetry breaking. The twelve-flavor β-function emerges as closest to the CW, perhaps near-conformal, or perhaps with an infrared fixed point (IRFP) at some unexplored strong coupling inside the CW. It is premature to speculate on dilaton properties of the twelveflavor model since the near-conformal realization remains an open question. However, it is interesting and important to investigate dilaton tests of the light sextet scalar whose β-function is closest to the CW in the symmetry breaking phase and emerges as the leading candidate for dilaton tests of the light scalar. We report results from high precision analysis of the twelve-flavor β-function [1] refuting its published IRFP [2,3]. We present our objections to recent claims [4,5] for non-universal behavior of staggered fermions used in our analysis. We also report our first analysis of dilaton tests of the light 0 ++ scalar in the sextet model and comment on related post-conference developments. The dilaton test is the main thrust of this conference contribution including presentation #405 on the n f = 12 β-function and presentation #260 on dilaton tests of the sextet model. They are both selected from the near-conformal BSM paradigm. BSM β-functions close to the conformal windowThe investigations of the scale-dependent renormalized gauge couplings of strongly coupled gauge theories and their related β-functions focus on near-conformal infrared behavior in a well-defined presenter of contribution 405 presenter of contribution 260

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Section: Tests Of the Asymptotic Dilaton Potential V(χ) ∼ χ Pmentioning

confidence: 87%

The twelve-flavor β-function and dilaton tests of the sextet scalar

et al. 2018

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“…For SU(3) with R ¼ F and N f ¼ 8, as is evident in Table II, there is a significant difference between the values of our two Padé approximants, indicating that a calculation of the series to higher order in Δ f than OðΔ 4 f Þ would be desirable. This theory with N f ¼ 8 has been the subject of a number of lattice studies, including [58,59] (see also [60,61]), which have observed quasiconformal behavior. This behavior is consistent with the inference that for SU(3) and R ¼ F, the value N f ¼ 8 is close to, but slightly less than, N f;cr , in agreement with our estimate in Eq.…”

Section: ð3:17þmentioning

confidence: 99%

Physics of the non-Abelian Coulomb phase: Insights from Padé approximants

Ryttov

Shrock

2018

Phys. Rev. D

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We consider a vectorial, asymptotically free SUðN c Þ gauge theory with N f fermions in a representation R having an infrared (IR) fixed point. We calculate and analyze Padé approximants to scheme-independent series expansions for physical quantities at this IR fixed point, including the anomalous dimension, γψ ψ;IR , to OðΔ 4 f Þ, and the derivative of the beta function, β 0 IR , to OðΔ 5 f Þ, where Δ f is an N f -dependent expansion variable. We consider the fundamental, adjoint, and rank-2 symmetric tensor representations. The results are applied to obtain further estimates of γψ ψ;IR and β 0 IR for several SUðN c Þ groups and representations R, and comparisons are made with lattice measurements. We apply our results to obtain new estimates of the extent of the respective non-Abelian Coulomb phases in several theories. For R ¼ F, the limit N c → ∞ and N f → ∞ with N f =N c fixed is considered. We assess the accuracy of the scheme-independent series expansion of γψ ψ;IR in comparison with the exactly known expression in an N ¼ 1 supersymmetric gauge theory. It is shown that an expansion of γψ ψ;IR to OðΔ 4 f Þ is quite accurate throughout the entire non-Abelian Coulomb phase of this supersymmetric theory.

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“…Recently there has been renewed interest in effective field theories (efts) featuring the dilaton degree of freedom [24][25][26][28][29][30][31][32][33]. Going further away from the conformal window, we expect the dilaton state to merge into the lightest scalar state of the theory loosing its conformal properties, as properly encoded in the agnostic effective approach of [32]. This interest in the dilaton state is due to lattice studies of SU (3) gauge theories with matter field content consisting of N f = 8 fundamental Dirac fermions [34][35][36][37], and N f = 3 symmetric 2-index Dirac fermions (sextet) [38][39][40] known as Minimal Walking Technicolor [11,24,25,41].…”

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confidence: 99%

Near-conformal dynamics at large charge

2020

Self Cite

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We investigate four-dimensional near-conformal dynamics by means of the large-charge limit. We first introduce and justify the formalism in which near-conformal invariance is insured by adding a dilaton and then determine the large-charge spectrum of the theory. The dilaton can also be viewed as the radial mode of the effective field theory. We calculate the two-point functions of charged operators. We discover that the mass of the dilaton, parametrising the near-breaking of conformal invariance, induces a novel term that is logarithmic in the charge. One can therefore employ the large-charge limit to explore near-conformal dynamics and determine dilaton-related properties.

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Extending chiral perturbation theory with an isosinglet scalar

Cited by 65 publications

References 70 publications

The twelve-flavor β-function and dilaton tests of the sextet scalar

The twelve-flavor β-function and dilaton tests of the sextet scalar

Physics of the non-Abelian Coulomb phase: Insights from Padé approximants

Near-conformal dynamics at large charge

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