Searches for pair production of supersymmetric particles under the assumpti
on that R-parity is not conserved are presented, based on data recorded by
the DELPHI detector in 1998 from e(+)e(-) collisions at a centre-of-mass en
ergy of 189 GeV. Only one R-parity violating LL (E) over bar term (i.e. one
lambda coupling), which couples scalar leptons to leptons, is considered t
o be dominant at a time. Moreover, it is assumed that the strength of the R
-parity violating couplings is such that the lifetimes can be neglected. Th
e search for pair production of neutralinos, charginos and sleptons has bee
n performed for both direct R-parity violating decays and indirect cascade
decays. The results are in agreement with Standard Model expectations, and
are used to update the constraints on the MSSM parameter values and the mas
s limits previously derived at root s = 183 GeV. The present 95% C.L. Limit
s on supersymmetric particle masses are:
m(<(chi)over tilde>0) > 30 GeV/c(2) and m(<(chi)over tilde>+/-) > 94 GeV/c(
2);
m(<(nu)over tilde>) > 76.5 GeV/c(2) (direct and indirect decays);
m((l) over tilde R) > 83 GeV/c(2) (indirect decay only).
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