Gluino Windows
Although it has been known since the mid-seventies that light gluinos are an aesthetically appealing and phenomenologically viable path to a future particle physics, it has only been since 1992 that positive indications have been pointed out that nature may in fact have chosen this path. Many of these indications are weak at best. Nevertheless, if they are caused by statistical fluctuations in the data, it is amazing that these fluctuations seem so often to be in the direction to favor a light gluino rather than in the opposite direction. The current limits on squark and gluino masses in the low gluino mass region are indicated in the figure below which has evolved from an early chart given by Dawson, Einhorn, and Quigg (Phys. Rev. D31, 1581, 1985). An intermediate stage appeared in the UA1 paper, C. Albajar et al, Phys. Lett. B198, 261, 1987. (See, however, the note at the bottom of this page for some new analysis).
Regions in the gluino mass - squark mass plane ruled out by various experiments are indicated. White spaces are still allowed. The lowest gluino mass windows are ruled out by the KTeV experiment if the photino is significantly lighter than the gluino-gluon bound state (R0).
In a recent preprint by Patrick Janot (hep-ph/0302076) it is argued that, unless there are finely tuned conspiracies in Z decay, all the gluino windows corresponding to gluino masses below 6.3 GeV/c2 are now excluded.
