Electroweak precision measurements and collider probes of the standard model with large extra dimensions - art. no. 016007

The elementary particles of the standard model may reside in more than 3 1 dimensions. We study the consequences of large compactified dimensions on scattering and decay observables at high-energy colliders. Our analysis in cludes global fits to electroweak precision data, indirect tests at high-en ergy electron-positron colliders (CERN LEP2, and NLC), and direct probes of the Kaluza-Klein resonances at hadron colliders (Fermilab Tevatron and CER N LHC). The present limits depend sensitively on the Higgs sector, both the mass of the Higgs boson and how many dimensions it feels. Lf the Higgs bos on is trapped on a (3 + 1)-dimensional wall with the fermions, large Higgs boson masses (up to 500 GeV) and relatively light Kaluza-Klein mass scales (less than 4 Tev) can provide a good fit to precision data. That is, a ligh t Higgs boson is not necessary to At the electroweak precision data, as it is in the standard model. If the Higgs boson propagates in higher dimension s, precision data prefer a light Higgs boson (less than 260 GeV) and a high er compactification scale (greater than 3.8 TeV). Future colliders can prob e much larger scales. For example, a 1.5 TeV electron-positron linear colli der can indirectly discover Kaluza-Klein excitations up to 31 TeV if 500 fb (-1) integrated luminosity is obtained.