Discovery of supersymmetry with degenerated mass spectrum
  Discovery of supersymmetric (SUSY) particles at the Large Hadron Collider(LHC) has been studied for the models where squarks and gluino are much heavier than the lightest supersymetric particle (LSP). In this paper, we investigate the SUSY discovery in the models with degenerated mass spectrum up to m_LSP~0.7 m_sq. Such mass spectrum is predicted in certain parameter region of the mixed modulas anomaly mediation (MMAM) model. We find that the effective transverse mass of the signal for the degenerated parameters shows the distribution similar to that of the background. Experimental sensitivity of the SUSY particles at the LHC therefore depends on the uncertainty of the background in this class of model. We also find that SUSY signal shows an interesting correlation between M_eff and ETmiss which may be used to determine the signal region properly to enhance the S/N ratio even if the sparticle masses are rather degenerated. The structure is universal for the models with new heavy colored particles decaying into visible particles and a stable neutral particle, dark matter. 
Kiyotomo Kawagoe and Mihoko M. Nojiri