SUSY Higgs at the LHC : Effects of light charginos and neutralinos

In view of the latest LEP data we consider the effects of charginos andneutralinos on the two-photon and bbbar signatures of the Higgs at the LHC.Assuming the usual GUT inspired relation between M_1 and M_2 we show that thereare only small regions with moderate tanbeta and large stop mixings that may bedangerous. Pathological models not excluded by LEP which have degeneracybetween the sneutrino and the chargino are however a real danger because oflarge branching fraction of the Higgs into invisibles. We have also studiedmodels where the gaugino masses are not unified at the GUT scale. We takeM_1=M_2/10 as an example where large reductions in the signal at the LHC canoccur. However we argue that such models with a very light neutralino LSP maygive a too large relic density unless the sleptons are light. We then combinethis cosmological constraint with neutralino production with light sfermions tofurther reduce the parameter space that precludes observability of the Higgs atthe LHC. We still find regions of parameter space where the drops in the usualHiggs signals at the LHC can be drastic. Nonetheless, in such scenarios whereHiggs may escape detection we show that one should be able to produce allcharginos and neutralinos. Although the heavier of these could cascade into theHiggs, the rates are not too high and the Higgs may not always be recoveredthis way