The current uncertainty on the parametrization of the partonic content of the
proton (PDF's) affects the potential for the discovery of new physics at LHC.
The study of Z boson production in association with a b-jet can considerably
reduce such uncertainty. In addition, this process represents a background both
to the search for the Higgs boson and for SUSY particles. We present an update,
based on the full simulation data sample produced for the Rome Physics
Workshop, of a preliminary study in the case where the Z boson decays in mu+
mu-.Comment: 16 page
