  The Xi(1690)0 resonance is observed in the Lambda anti-K0 channel in the
decay Lambdac+ --> Lambda anti-K0 K+, from a data sample corresponding to a
total integrated luminosity of ~ 200 fb-1 recorded by the Babar detector at the
PEPII asymmetric-energy e+ e- collider operating at ~ 10.58 GeV and ~ 10.54 GeV
center-of-mass energies. A fit to the Dalitz plot intensity distribution
corresponding to the coherent superposition of amplitudes describing Lambda
a0(980)+ and Xi(1690)0 K+ production yields mass and width values of 1684.7 +/-
1.3 (stat.) +2.2 -1.6 (syst.) MeV/c2, and $8.1 +3.9 -3.5 (stat.) +1.0 -0.9
(syst.) MeV, respectively, for the Xi(1690)0, while the spin is found to be
consistent with value of 1/2 on the basis of studies of the (Lambda KS) angular
distribution.
