Partial compositeness and baryon matrix elements on the lattice

Ayyar, Venkitesh; DeGrand, Thomas; Hackett, Daniel C.; Jay, Walter M.; Neil, Ethan T.; Shamir, Yigal; Svetitsky, Benjamin

doi:10.1103/physrevd.99.094502

Cited by 59 publications

(70 citation statements)

References 52 publications

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“…We perform the extrapolation to the massless limit. The masses of V, AV, and S states are m V /f PS = 8.08 (32), m AV /f PS = 13.4(1.5), and m S /f PS = 14. 2(1.7).…”

Section: Continuum Results: Summarymentioning

confidence: 99%

“…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%

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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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“…We perform the extrapolation to the massless limit. The masses of V, AV, and S states are m V /f PS = 8.08 (32), m AV /f PS = 13.4(1.5), and m S /f PS = 14. 2(1.7).…”

Section: Continuum Results: Summarymentioning

confidence: 99%

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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“…Blue circles are for the models M6 and M12, while the red diamond is for the model M11 and the black square for the lattice SU (4) model considered in Refs. [21][22][23][24][25][26]. global symmetry breaking [21,23].…”

Section: Applications To Two-representation Composite Higgs Mod-elsmentioning

confidence: 99%

Into the conformal window: Multirepresentation gauge theories

2020

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We investigate the conformal window of four-dimensional gauge theories with fermionic matter fields in multiple representations. Of particularly relevant examples are the ultra-violet complete models with fermions in two distinct representations considered in the context of composite Higgs and top partial-compositeness. We first discuss various analytical approaches to unveil the lower edge of the conformal window and their extension to the multiple matter representations. In particular, we argue that the scheme-independent series expansion for the anomalous dimension of a fermion bilinear at an infrared fixed point, γχ χ, IR , combined with the conjectured critical condition, γχ χ, IR = 1 or equivalently γχ χ, IR (2−γχ χ, IR ) = 1, can be used to determine the boundary of conformal phase transition on fully physical grounds. In illustrative cases of SU (2) and SU (3) theories with N R Dirac fermions in various representations, we assess our results by comparing to other analytical or lattice results. *

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“…These assumptions can be checked on the lattice since our fundamental matter content is vector-like. Thus, our model is a good candidate to produce realistic top couplings in a lattice study like [33].…”

Section: Discussionmentioning

confidence: 97%

Lattice-friendly gauge completion of a composite Higgs with top partners

Gertov

Nelson

Perko

et al. 2019

J. High Energ. Phys.

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We give an explicit example of a composite Higgs model with a pseudo-Nambu-Goldstone Higgs in which the top Yukawa coupling is generated via the partial compositeness mechanism. This mechanism requires composite top partners which are relatively light compared to the typical mass scale of the strongly coupled theory. While most studies of the phenomenology of such models have focused on a bottom-up approach with a minimal effective theory, a top-down approach suggests that the theory should contain a limit in which an unbroken global chiral symmetry protects the mass of the top partners, and the spectrum of the partners satisfies 't Hooft matching conditions. We find that the relatively light fermions and pseudo-Goldstone bosons fall into complete multiplets of a large approximate global symmetry, and that the spectrum of particles lighter than a few TeV is non-minimal. Our example illustrates the likely features of a such a composite Higgs theory and also serves as an example of a non-chiral theory with a possible solution to the 't Hooft matching conditions. We find in this example that for some low-energy parameters in the effective theory the top partners can decay into high-multiplicity final states, which could be difficult for the Large Hadron Collider (LHC) to constrain. This may potentially allow for the top partners to be lighter than those in more minimal models.

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Partial compositeness and baryon matrix elements on the lattice

Cited by 59 publications

References 52 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

Into the conformal window: Multirepresentation gauge theories

Lattice-friendly gauge completion of a composite Higgs with top partners

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