Novel Higgs Decays and Dark Matter in the E(6)SSM

Abstract

The Exceptional Supersymmetric (SUSY) Standard Model predicts three families of Higgs doublets plus three Higgs singlets, where one family develops vacuum expectation values (VEVs), while the remaining two which do not are called Inert. The model can account for the dark matter relic abundance if the two lightest Inert neutralinos, identified as the (next-to) lightest SUSY particles ((N)LSPs), have masses close to half the Z mass. In this case we find that the usual SM-like Higgs boson decays more than 95% of the time into either LSPs or NLSPs. The latter case produces a final state containing two leptons l^{+}l^{-} with an invariant mass less than or about 10 GeV. We illustrate this scenario with a set of benchmark points satisfying phenomenological constraints and the WMAP dark matter relic abundance. This scenario also predicts other light Inert chargino and neutralino states below 200 GeV, and large LSP direct detection cross-sections close to current limits and observable soon at XENON100.Comment: 39 pages, 2 figures, some minor changes to the text, references added, version to appear in Phys. Rev.