Universal Extra Dimensions after Higgs Discovery Takuya Kakuda, ∗ Kenji Nishiwaki, † Kin-ya Oda,‡

We show bounds on five- and six-dimensional universal extra dimension (UED) models from the latest results of the Higgs searches at the LHC and from the electroweak precision data for the S and T parameters. We consider the minimal UED model in five dimensions and the ones in six dimensions, compactified on T 2/Z2, T 2/(Z2 × Z ′2), T 2/Z4, S2, S2/Z2, the real projective plane, and the pro-jective sphere. The highest possible ultraviolet cutoff scale for each UED model is evaluated from the electroweak vacuum stability by solving the renormalization group equation of the Higgs self coupling. This scale turns out to be lower than the conventional one obtained from the perturbativity of the gauge coupling. The resultant 95 % CL lower bounds on the first KK scale from the LHC results and from the S, T analysis are 650 and 700 GeV in the minimal UED model, respec-tively, while those in the 6D UED models are 850–1350 GeV and 900–1500 GeV, respectively. HRI-P-13-02-00