Warping the universal extra dimensions

Abstract

We develop the necessary ingredients for the construction of realistic models with warped universal extra dimensions. Our investigations are based on the seven dimensional (7D) spacetime AdS 5 × T 2 /Z 2 and we derive the Kaluza-Klein (KK) spectra for gravitons, bulk vectors and the TeV brane localized Higgs boson. We show that, starting with a massive 7D fermion, one may obtain a single chiral massless mode whose profile is readily localized towards the Planck or TeV brane. This allows one to place the standard model fermions in the bulk and construct models of flavor as in Randall-Sundrum models. Our solution also admits the familiar KK parity of UED models so that the lightest odd KK state is stable and may be a dark matter (DM) candidate. As an additional feature the AdS 5 warping ensures that the excited modes on the torus, including the DM candidate, appear at TeV energies (as is usually assumed in UED models) even though the Planck scale sets the dimensions for the torus. 1

Reducing constraints in a higher dimensional extension of the Randall and Sundrum model

“…If there are then one must either include additional operators [48,49] or use a different parameterisation. In the above scenario one would receive non oblique correction once you have rotated into the mass eigenstate and acted (25) on the covariant derivative (23). However if one assumes universal corrections to the gauge fermion couplings, or equivalently that all the fermions are sitting at the same point, then one can make a field redefinition to absorb the non oblique corrections [13]…”

“…The principal motivation for such a choice is that it is one of the simplest extensions to the RS model that allows the investigation of the phenomenological implications of warping the D > 5 additional dimensions and testing the robustness of the 5D phenomenology. Work has already been done looking at the phenomenology of AdS 5 × M δ [20,21] as well as AdS D [22,23,24] and for additional work on 6D RS models see for example [25,26,27,28]. The work very much continues from [29] where it was demonstrated that if the additional spaces are increasingly (decreasingly) warped towards the IR brane then the couplings of KK gauge fields propagating in the bulk will be suppressed (enhanced) relative to the zero mode couplings.…”

Warped universal extra dimensions

“…a KK parity similar to the one present in Universal Extra Dimensional scenarios or UED's [24,25]). As a result, the lightest KK-parity odd particle (the LKP) is stable, and a potential dark matter (DM) candidate (for an alternative proposal, see [26]). However, unlike in UED scenarios [27,28], the KK states are not necessarily highly degenerate, with the degeneracy broken by loop-level effects, but instead larger mass splittings can be expected (although there are some interesting degeneracies, related to localization effects).…”

Warped radion dark matter

“…where g * is the effective number of relativistic degrees of freedom at the time of r decoupling, M P l = 1.22×10 19 GeV is the Planck mass, and x F = m r /T F gives the freeze-out temperature by solving for…”

“…A concrete model that stabilizes the interbrane distance, and hence gives mass to the radion field, while at the same time leading to the existence of a KK-parity symmetry, was proposed in Ref. [18] (see [19] for an alternative proposal). Indeed, it is found that generically the LKP is the first KK-radion mode.…”