Possible Effects of a Hidden Valley on Supersymmetric Phenomenology
  A hidden valley sector may havea profound impact on the classic phenomenology of supersymmetry. This occurs if the LSP lies in the valley sector. In addition to reducing the standard missing energy signals and possibly providing displaced vertices (phenomena familiar from gauge-mediated and R-parity-violating models) it may lead to a variable multiplicity of new neutral particles, whose decays produce soft jets and/or leptons, and perhaps additional displaced vertices. Combined, these issues might obscure supersymmetric particle production from search strategies used on current Tevatron data and planned for the LHC. The same concerns arise more generally for any model that has a symmetry (such as T-parity or KK-parity) realized nontrivially in both the standard-model and the hidden-valley sectors. Possible strategies for experimental detection are discussed, and the potential importance of the LHCb detector is noted. 
Matthew J. Strassler (U. Washington, Seattle)