Abstract
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 phenomenological 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 $y_m=1+\gamma^*= 1.47(5)$ suggesting that $N_f=10$ 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 $0^{++}$ isosinglet scalar.
Highlights
For gauge theories describing the Higgs sector as a composite structure, experimental observations imply that a large separation of scales between the electroweak scale (IR) and new ultraviolet physics (UV) [4,5,6,7,8,9,10,11] is required
We show that physical masses exhibit hyperscaling and determine the universal mass scaling dimension of the corresponding Nf 1⁄4 10 system ym 1⁄4 1 þ γ⋆m 1⁄4 1.47ð5Þ
This value is smaller than expected for a theory near the edge of the conformal window suggesting that Nf 1⁄4 9 or 8 flavor models could be closer to the sill of the conformal window
Summary
Experiments have discovered a 125 GeV Higgs boson [1,2,3] but so far, up to a few TeV, no direct signs of physics. Theories with a large separation of scales part company from QCD, exhibiting a “walking” gauge coupling [12,13,14], and providing a dynamical mechanism for electroweak (EW) symmetry breaking. By choosing a theory with four fermions in the light, chirally broken sector, our simulations can directly be related to existing models extending the SM with a new strongly interacting sector [41,42,43] In these models the Higgs boson is a pseudo-Nambu-Goldstone boson (pNGB) of the new strong sector [41,42,44,45,46]. We explore this new, strongly coupled theory by performing large scale numerical lattice-field-theory simulations. Preliminary results have been reported in [56,57]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
