  We study how the properties of the four neutralino states, chi_i (i = 1, 2,
3, 4), can be investigated at the Large Hadron Collider (LHC), in the case when
the lightest one, chi_1, has a mass m_chi < 50 GeV and is stable. This
situation arises naturally in supersymmetric models where gaugino masses are
not unified at a Grand Unified (GUT) scale and R-parity is conserved. The main
features of these neutralino states are established by analytical and numerical
analyses, and two scenarios are singled out on the basis of the cosmological
properties required for the relic neutralinos. Signals expected at LHC are
discussed through the main chain processes started by a squark, produced in the
initial proton-proton scattering. We motivate the selection of some convenient
benchmarks, in the light of the spectroscopical properties (mass spectrum and
transitions) of the four neutralino states. Branching ratios and the expected
total number of events are derived in the various benchmarks, and their
relevance for experimental determination of neutralino properties is finally
discussed.
