Abstract
In the context of gauge/gravity dualities, we calculate the scalar and tensor mass spectrum of the boundary theory defined by a special 8-scalar sigma-model in five dimensions, the background solutions of which include the 1-parameter family dual to the baryonic branch of the Klebanov–Strassler field theory. This provides an example of a strongly-coupled, multi-scale system that yields a parametrically light mass for one of the composite scalar particles: the dilaton. We briefly discuss the implications of these findings towards identifying a satisfactory solution to both the big and little hierarchy problems of the electro-weak theory.
Highlights
Many extensions of the Standard Model (SM) of particle physics are motivated by the hierarchy problem
We provide a calculable example of a stronglycoupled theory that realizes this scenario, it does not implement electro-weak symmetry breaking
All the qualitative expectations emerging from the study of the field theory are confirmed quantitatively by the gravity dual, including the fact that the spectrum of glueballs along the baryonic branch deconstructs a compact manifold, and interpolates between the known spectra of the KS and CVMN backgrounds
Summary
Many extensions of the Standard Model (SM) of particle physics are motivated by the (big) hierarchy problem. New dynamics and symmetries stabilize the electroweak scale, leading to the expectation that new particles should appear just above it. Besides the calculability limitations of a strongly-coupled theory, the discovery of the Higgs particle [1] exacerbates the little hierarchy problem in such scenario, as one would have expected a proliferation of bound states to appear above the electroweak scale. To make strongly-coupled models viable, it is imperative to find an example of a strongly-coupled, four-dimensional theory, no matter what the microscopic origin, that exhibits one scalar state parametrically lighter than the plethora of bound states. Discuss their origin, potential applications, and limitations
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