Lone Higgs boson at the CERN LHC

Abstract

We address the possible scenario that the Large Hadron Collider (LHC) discovers only a Higgs boson after $10\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of operation, and attempt to identify this Higgs boson as that of the standard model, the minimal universal extra dimension model, the littlest Higgs model with $T$-parity (LHT), or the minimal supersymmetric standard model (MSSM), using only the measurement of the product of gluon-fusion production cross section and the di-photon branching ratio. In the minimal universal extra dimension model, by decoupling any new physics sufficiently to evade the discovery reach at the LHC, the deviation of the signal from the SM is not statistically significant. However, in LHT and MSSM, it is possible to have a significant deviation in the signal that is consistent with this ``lone Higgs scenario,'' and, in the case of a very large suppression, we can distinguish MSSM and LHT before the discovery of any new resonances. Starting with the lone Higgs scenario and the deviation in this measurement from the standard model prediction (whether or not statistically significant), we offer tests that may discriminate the models and search strategies of discovering new physics signatures with increasing integrated luminosity.