The Clockwork Standard Model

Abstract

We consider various bulk fields with general dilaton couplings in the linear dilaton background in five dimensions as the continuum limit of clockwork models. We show that the localization of the zero modes of bulk fields and the mass gap in the KK spectrum depend not only on the bulk dilaton coupling, but also on the bulk mass parameter in the case of a bulk fermion. The consistency from universality and perturbativity of gauge couplings constrain the dilaton couplings to the brane-localized matter fields as well as the bulk gauge bosons. Constructing the Clockwork Standard Model (SM) in the linear dilaton background, we provide the necessary conditions for the bulk mass parameters for explaining the mass hierarchy and mixing for the SM fermions. We can introduce a sizable expansion parameter ε = e − 2 3 kzc for the realistic flavor structure in the quark sector without a fine-tuning in the bulk mass parameters, but at the expense of a large 5D Planck scale. On the other hand, we can use a smaller expansion parameter for lepton masses, in favor of the solution to the hierarchy problem of the Higgs mass parameter. We found that massive Kaluza-Klein (KK) gauge bosons and massive KK gravitons couple more strongly to light and heavy fermions, respectively, so there is a complementarity in the resonance researches for those KK modes at the LHC.

FIMP Dark Matter in Clockwork/Linear Dilaton extra-dimensions

“…Throughout the paper, we consider all the SM and DM fields localized on the IR-brane, whereas on the UV-brane we could have any other physics that is Planck-suppressed (see ref. [41] for a scenario where all SM fields may be bulk fields). We assume that DM particles only interact with the SM particles gravitationally by considering only DM singlets under the SM gauge group.…”

Lectures on physics beyond the Standard Model

“…The clockwork mechanism is to obtain hierarchically small couplings in models with multiple symmetries due to the localization in the field space [66][67][68][69][70][71]. It can address the hierarchy problem and the flavor problem, etc, in the SM, by introducing multiple copies of the SM particles.…”

Aspects of compactification on a linear dilaton background

“…The aim of this subsection is to remind some general results regarding the spectrum of bosonic fields on a linear dilaton background, and then motivate the first part of the work carried out in this paper, which will be described in section 3. We start with the case of a bulk scalar and vector fields in five dimensions, an analysis which can be found for instance in [22,23], before moving to the spin-0 and spin-1 spectrum of the 5D dilaton-gravity theory described in the previous subsection.…”