We consider the possibility that the gravitino might be the lightest supersymmetric particle (LSP) in the constrained minimal extension of the Standard Model (CMSSM). In this case, the next-to-lightest supersymmetric particle (NSP) would be unstable, with an abundance constrained by the concordance between the observed light-element abundances and those calculated on the basis of the baryon-to-entropy ratio determined using CMB data. We modify and extend previous CMSSM relic neutralino calculations to evaluate the NSP density, also in the case that the NSP is the lighter stau, and show that the constraint from late NSP decays is respected only in a limited region of the CMSSM parameter space. In this region, gravitinos might constitute the dark matter.
|Original language||English (US)|
|Number of pages||10|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - May 20 2004|
Bibliographical noteFunding Information:
We would like to thank Rich Cyburt for providing us with BBN analysis data, and Stefan Groot Nibbelink for helpful conversations. Y.S. would like to thank Richard Arnowitt for useful discussions. We would also like to thank Koichi Hamaguchi for constructive comments regarding the original version of the manuscript. The work of K.A.O., Y.S., and V.C.S. was supported in part by DOE Grant DE-FG02-94ER-40823.