Search for universal extra dimensions in ppbar collisions

Full text: We present a search for Kaluza-Klein (KK) particles predicted by models with universal extra dimensions which allows all Standard Model fields to propagate in the bulk. We have special interesting in the minimal model of universal extra dimensions, requiring only one extra dimension, compactified in a S1/Z2 orbifold, and the first level of Kaluza-Klein modes. This model is parametrized by the size R of the extra dimension and a cutoff scale Δ. This search uses a data set corresponding to an integrated luminosity of 7.3 fb-1, collected by the D0 detector at a pp-bar center of mass energy of 1.96 TeV produced by the Tevatron collider at Fermilab. The decay chain of KK particles can lead to a final state with two muons of the same charge, missing transverse energy and jets. This channel is characterized by having muons with low transverse momentum and a branching ratio of approximately 1% considering all production mechanisms. The background is dominated by QCD processes, which is modeled by data. Since no excess of data is observed, this signature is used to set a lower limit on the compactification scale of R-1 > 260 GeV at 95% C.L. in a minimal UED model, corresponding to a mass of 317 GeV of the lightest KK quark in this model. (author)