There are good reasons to consider models of low-energy supersymmetry with
very light photinos and gluinos. In a wide class of models the lightest
R-odd, color-singlet state containing a gluino, the 0Ëš, has a mass in the
1-2 GeV range and the slightly lighter photino, \pho, would survive as the
relic R-odd species. For the light photino masses considered here, previous
calculations resulted in an unacceptable photino relic abundance. But we point
out that processes other than photino self-annihilation determine the relic
abundance when the photino and R0 are close in mass. Including
\r0\longleftrightarrow\pho processes, we find that the photino relic
abundance is most sensitive to the 0Ëš-to-\pho mass ratio, and within model
uncertainties, a critical density in photinos may be obtained for an
0Ëš-to-\pho mass ratio in the range 1.2 to 2.2. We propose photinos in the
mass range of 500 MeV to 1.6 GeV as a dark matter candidate, and discuss a
strategy to test the hypothesis.Comment: uuencoded compressed tar file containing 32 page LaTeX file and eight
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