  The LHC has recently released precise measurements of the transverse momentum
distribution of the Z-boson that provide a unique constraint on the structure
of the proton. Theoretical developments now allow the prediction of these
observables through next-to-next-to-leading order (NNLO) in perturbative QCD.
In this work we study the impact of incorporating these latest advances into a
determination of parton distribution functions (PDFs) through NNLO including
the recent ATLAS and CMS 7 TeV and 8 TeV $p_T^Z$ data. We investigate the
consistency of these measurements in a global fit to the available data and
quantify the impact of including the $p_T^Z$ distributions on the PDFs. The
inclusion of these new data sets significantly reduces the uncertainties on
select parton distributions and the corresponding parton-parton luminosities.
In particular, we find that the $p_T^Z$ data ultimately leads to a reduction of
the PDF uncertainty on the gluon-fusion and vector-boson fusion Higgs
production cross sections by about 30%, while keeping the central values nearly
unchanged.
