Discovery of supersymmetry with degenerate mass spectrum

The discovery of supersymmetric (SUSY) particles at the Large Hadron Collider (LHC) has been studied for models where the squarks and gluino are much heavier than the lightest supersymmetric particle. In this paper, we investigate SUSY discovery in models with a degenerate mass spectrum up to m(LSP)less than or similar to 0.7m(q). Such a mass spectrum is predicted in a certain parameter region of the mixed modulus anomaly mediation model. We find that the effective transverse mass of the signal for the degenerate parameters shows a distribution similar to that of the background. Experimental sensitivity to the SUSY particles at the LHC therefore depends on the uncertainty of the background in this class of model. We also find that the SUSY signal shows an interesting correlation between M-eff and E-T which may be used to better determine the signal region and enhance the S/N ratio even if the sparticle masses are rather degenerate. This correlation is universal for models with new heavy colored particles decaying into visible particles and a stable neutral dark matter.