Nonstandard string-SUSY scenario and its phenomenological implications

We investigate the phenomenology of an orbifold string model in which supersymmetry breaking is dominated by the overall open-quotes sizeclose quotes modulus field and all matter fields are in the untwisted sector. The possibly close degeneracy of the lightest neutralino and chargino and the possibly small splitting between the gluino and chargino or LSP mass imply that discovery of supersymmetry at future colliders could be more challenging than anticipated. Specialized search strategies and particular detector features could play an important role. For preferred model parameter choices, the phenomenology of dark matter in the universe is significantly modified. copyright 1997 The American Physical Society