Strong dynamics with matter in multiple representations: $$\mathrm {SU}(4)$$ gauge theory with fundamental and sextet fermions

Cossu, Guido; Debbio, Luigi Del; Panero, Marco; Preti, David

doi:10.1140/epjc/s10052-019-7137-1

Cited by 49 publications

(60 citation statements)

References 40 publications

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“…Some results about the (quenched) spectrum of mesons in the theory with this field content will be presented in Ref. [83], but the implementation of fully dynamical calculations with multiple fermion representations will require a significant amount of development, with only few examples of calculations of this type existing in the current literature [28,32,37,85,118].…”

Section: Discussionmentioning

confidence: 99%

Sp (4) gauge theories on the lattice: Nf = 2 dynamical fundamental fermions

Bennett

Hong

Lee

et al. 2019

J. High Energ. Phys.

135

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We perform lattice studies of the gauge theory with Sp(4) gauge group and two flavours of (Dirac) fundamental matter. The global SU (4) symmetry is spontaneously broken by the fermion condensate. The dynamical Wilson fermions in the lattice action introduce a mass that breaks the global symmetry also explicitly. The resulting pseudo-Nambu-Goldstone bosons describe the SU (4)/Sp(4) coset, and are relevant, in the context of physics beyond the Standard Model, for composite Higgs models. We discuss scale setting, continuum extrapolation and finite volume effects in the lattice theory. We study mesonic composite states, which span representations of the unbroken Sp(4) global symmetry, and we measure masses and decay constants of the (flavoured) spin-0 and spin-1 states accessible to the numerical treatment, as a function of the fermion mass. With help from the effective field theory treatment of such mesons, we perform a first extrapolation towards the massless limit. We assess our results by critically comparing to the literature on other models and to the quenched results, and we conclude by outlining future avenues for further exploration. The results of our spectroscopic analysis provide new input data for future phenomenological studies in the contexts of composite Higgs models, and of dark matter models with a strongly coupled dynamical origin. arXiv:1909.12662v2 [hep-lat] 22 Nov 2019 7 Comparison to other gauge theories 37 8 Continuum results: summary 42 9 Conclusions and outlook 43 A Lattice action and numerical calculations: additional details 45 A.1 Hybrid Monte Carlo 45 A.2 Of diquarks 47 A.3 Effective mass and fitting procedure 48 B Low-energy constants and global fit 50 -1 -

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Section: Discussionmentioning

confidence: 99%

Sp (4) gauge theories on the lattice: Nf = 2 dynamical fundamental fermions

Bennett

Hong

Lee

et al. 2019

J. High Energ. Phys.

135

View full text Add to dashboard Cite

show abstract

“…(6.2). For completeness, we mention another independent lattice analysis [112] of the very same model with a different lattice setup, giving complementary results. Since this paper does not address the chiral and continuum extrapolations, we do not elaborate further.…”

Section: Jhep03(2021)182mentioning

confidence: 94%

Holographic models of composite Higgs in the Veneziano limit. Part I. Bosonic sector

Elander

Frigerio

Knecht

et al. 2021

J. High Energ. Phys.

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We study strongly-coupled, approximately scale-invariant gauge theories, which develop a mass gap in the infrared. We argue that a large number of fermion flavours is most suitable to provide an ultraviolet completion for the composite Higgs scenario. The holographic approach allows to describe the qualitative features of the non-perturbative dynamics in the Veneziano limit. We introduce new bottom-up holographic models, which incorporate the backreaction of flavour on the geometry, and show that this can correlate the mass gap to the scale of flavour-symmetry breaking. We compute the mass spectrum for the various composite bosonic states, and study its dependence on the scaling dimension of the symmetry-breaking operators, as well as on the number of flavours. The different regions with a light dilaton are critically surveyed. We carefully assess the domain of validity of the holographic approach, and compare it with lattice simulations and the Nambu-Jona-Lasinio model.

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“…The introduction of diagonal mass terms for the fermions is compatible (aligned) with the vacuum structure, and provides a degenerate non-vanishing mass for the resulting 5 + 20 pNGBs. The lattice treatment of such a system with multiple dynamical fermion representations is a novel arena for lattice gauge theories, and only recently have calculations of this type been published, in the specific context of theories with SU (4) gauge group [21,27,29,33,38].…”

Section: Contentsmentioning

confidence: 99%

Sp(4) gauge theories on the lattice: Quenched fundamental and antisymmetric fermions

et al. 2020

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We perform lattice studies of meson mass spectra and decay constants of the Sp(4) gauge theory in the quenched approximation. We consider two species of (Dirac) fermions as matter field content, transforming in the 2-index antisymmetric and the fundamental representation of the gauge group, respectively. All matter fields are formulated as Wilson fermions. We extrapolate to the continuum and massless limits, and compare to each other the results obtained for the two species of mesons. In the case of two fundamental and three antisymmetric fermions, the long-distance dynamics is relevant for composite Higgs models. This is the first lattice study of this class of theories. The global SU (4) × SU (6) symmetry is broken to the Sp(4) × SO(6) subgroup, and the condensates align with the explicit mass terms present in the lattice formulation of the theory.The main results of our quenched calculations are that, with fermions in the 2-index antisymmetric representation of the group, the masses squared and decay constant squared of all the mesons we considered are larger than the corresponding quantities for the fundamental representation, by factors that vary between ∼ 1.2 and ∼ 2.7. We also present technical results that will be useful for future lattice investigations of dynamical simulations, of composite chimera baryons, and of the approach to large-N in the Sp(2N ) theories considered. We briefly discuss their high-temperature behaviour, where symmetry restoration and enhancement are expected. We acknowledge useful discussions withWe summarise in this Appendix our conventions in the treatment of spinors, which are useful, for example, in switching between the 2-component and the 4-component notation (see also Ref. [50]). The former is best suited to highlight the symmetries of the system, while the latter is the formalism adopted as a starting point for the lattice numerical

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Strong dynamics with matter in multiple representations: $$\mathrm {SU}(4)$$ gauge theory with fundamental and sextet fermions

Cited by 49 publications

References 40 publications

Sp (4) gauge theories on the lattice: Nf = 2 dynamical fundamental fermions

Sp (4) gauge theories on the lattice: Nf = 2 dynamical fundamental fermions

Holographic models of composite Higgs in the Veneziano limit. Part I. Bosonic sector

Sp(4) gauge theories on the lattice: Quenched fundamental and antisymmetric fermions

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