A search for stable and long-lived heavy charged particles was performed us
ing the data taken by the DELPHI experiment at an energy of 189 GeV. The Ch
erenkov light detected in the Ring Imaging Cherenkov Detector and the ionis
ation loss measured in the Time Projection Chamber were used to identify he
avy particles passing through the detector. No evidence for the production
of such particles has been found, therefore exclusion limits at 95% confide
nce level were derived on the masses of left and right handed smuons and st
aus. The results were combined with previous DELPHI searches in this channe
l. Including previous DELPHI results, masses of left (right) handed stable
smuons and staus can be excluded between 2 GeV/c(2) and 88 (87.5) GeV/c(2)
at 95% CL. (C) 2000 Elsevier Science B.V. All rights reserved.