Cosmological constraints on supergravity unified models

Abstract

Supergravity GUT models with R-parity invariance possess a cold dark matter candidate (the lightest neutralino) with relic amounts consistent with astronomical measurements, and predict proton decay at rates accessible to on-going and future experiments. Future sattelite, balloon and ground based experiments will give precision determinations of the basic cosmological parameters, and thus affect accelerator and non-accelerator (p-decay, dark matter detection rate) predictions. Thus for the ΛCDM model we find an upper bound of gluino (neutralino) mass of about 520(70) GeV and for the HCDM model a bound of 720(100) GeV with gaps (forbidden regions) in the parameter space at lower masses. Kamiokande proton decay data combined with relic density constraints already excludes m g ̃ >400 GeV for minimal SU(5), and Super Kamiokande will be sensitive to m g ̃ >500 GeV for non-minimal models even for m 0 as large as 5 TeV. Proton decay and CDM relic density constraints also imply a reduction (by as much as 10 −3) in expected maximum CDM event rates for terrestial detectors.