  In this note we discuss a characteristic collider signature of models of
gauge mediated supersymmetry breaking in which the selectron and smuon are
mass-degenerate co-NLSP. In these models, all processes involving superpartners
give rise to two NLSP selectrons or smuons, each of which subsequently decays
to a nearly massless LSP gravitino and an electron or a muon. In a large region
of the parameter space, the NLSPs travel macroscopic distances, of the order
0.1-1000 mm, before they decay. Hence, these models give rise to collider
signatures involving charged tracks that end at vertices, which are inside the
detector volume but displaced with respect to the original collision point,
from which an electron or a muon is emitted. In order to probe this class of
models we propose a search for disappearing charged tracks in association with
displaced electrons or muons.
