Power law scaling in universal extra dimension scenarios

Abstract

We study the power law running of gauge, Yukawa and quartic scalar couplings in the universal extra dimension scenario where the extra dimension is accessed by all the standard model fields. After compactifying on an S 1 /Z 2 orbifold, we compute one-loop contributions of the relevant Kaluza-Klein (KK) towers to the above couplings up to a cutoff scale Λ. Beyond the scale of inverse radius, once the KK states are excited, these couplings exhibit power law dependence on Λ. As a result of faster running, the gauge couplings tend to unify at a relatively low scale, and we choose our cutoff also around that scale. For example, for a radius R ∼ 1 TeV −1 , the cutoff is around 30 TeV. We then examine the consequences of power law running on the triviality and vacuum stability bounds on the Higgs mass. We also comment that the supersymmetric extension of the scenario requires R −1 to be larger than ∼ 10 10 GeV in order that the gauge couplings remain perturbative up to the scale where they tend to unify.

Testing minimal universal extra dimensions using Higgs boson searches at the LHC

“…In practice, however, low energy observables are only weakly sensitive to the cut-off. For definiteness, in this paper, like in many of earlier works, as a benchmark point we take Λ = 20R −1 which is low enough to keep the SM coupling constants perturbative below the cut-off scale [1,26].…”

Two-loop corrections and predictability on orbifold

“…In this case, from the requirement of extracting physical quantities with higher derivative terms the value of ΛL may be constrained. In flat five dimensions, dependence of the gauge coupling on energy is usually large compared to the case of four dimensions [20,21]. For a large ΛL, models could give rise to g A = 0 or g A ≫ 1.…”

Exploring two universal extra dimensions at the CERN LHC

“…This could come about in a variety of ways. For example, an accurate measurement of the signal cross section would provide us with supplementary information about the mass scale 6 . Similarly, the discovery of any substructure in the M eff distribution would hint at (some of) the mass differences.…”

“…Apart from a very rich phenomenology (which can be probed by the LHC), these models offer gauge coupling unification at a relatively low scale of energy [4][5][6], and naturally contain a weakly interacting massive stable particle, which can be a suitable candidate for cold dark matter [7][8][9][10]. While the simplest UED scenario would have only one extra dimension (minimal UED or mUED model), a particularly interesting variant is the eponymous two Universal Extra Dimension (2UED) model [11,12].…”