Supersymmetric dark matter with a cosmological constant

Recent measurements of cosmological parameters from the microwave backgroun d radiation, type Ta supenovae, and the age of globular clusters help deter mine the relic matter density in the universe. It is first shown with mild cosmological assumptions that the relic matter density satisfies Omega(M)h( 2) < 0.6 independent of the cosmological constant and independent of the SN Ia data, including the SNIa data, the constraint becomes Omega(M)h(2) < 0.3 5. This result is then applied to supersymmetric models motivated by generi c features in supergravity mediated supersymmetry breaking. The result is a n upper bound on gaugino masses within reach of the LHC and a 1.5 TeV lepto n collider. Thus, cosmological considerations are beginning to limit the su persymmetric mass spectra in the experimentally verifiable range without re course to finetuning arguments, and without assuming a zero cosmological co nstant. (C) 1998 Elsevier Science B.V. All rights reserved.