  Using data from proton-antiproton collisions at Ecms=1.96 TeV recorded by the
CDF II detector at the Fermilab Tevatron, evidence for the excited resonance
state Lambda_b* is presented in its Lambda_b0 pi+ pi- decay, followed by the
Lambda_b0 -->Lambda_c+ (-->proton K- pi+) pi- decays. The analysis is based on
a data sample corresponding to an integrated luminosity of 9.6/fb collected by
an online event selection based on charged-particle tracks displaced from the
proton-antiproton interaction point. The significance of the observed signal is
3.5 Gaussian sigmas. The mass of the observed state is found to be 5919.22 +-
0.76 MeV in agreement with similar findings in proton-proton collision
experiments.
