  We describe parton density function sensitivity studies, using muon final
states produced through the Drell-Yan process via W, Z or $\gamma^*$ down to a
Q^2 of 10 GeV^2. This makes use of LHCb's unique ability to trigger on low
transverse momentum objects. Due to the forward acceptance of LHCb, x values
down to 2 10^{-6} can be probed, where with just 100 pb-1 of data, the gluon
PDF can improved up to 70%.
