Measurements of masses in supergravity models at CERN LHC

This paper presents new measurements in a case study of the minimal supergravity (SUGRA) model with ${m}_{0}=100\mathrm{GeV},$ ${m}_{1/2}=300\mathrm{GeV},$ ${A}_{0}=0,$ $\mathrm{tan}\ensuremath{\beta}=2,$ and $\mathrm{sgn}\ensuremath{\mu}=+$ based on four-body distributions from three-step decays and on minimum masses in such decays. These measurements allow masses of supersymmetric particles to be determined without relying on a model. The feasibility of testing slepton universality at the \ensuremath{\sim}0.1% level at high luminosity is discussed. In addition, the effect of enlarging the parameter space of the minimal SUGRA model is discussed. The direct production of left-handed sleptons and the nonobservation of additional structure in the dilepton invariant mass distributions are shown to provide additional constraints.