  We present a measurement of the Z boson differential cross section in
rapidity and transverse momentum using a data sample of pp collision events at
a centre-of-mass energy sqrt(s)=8 TeV, corresponding to an integrated
luminosity of 19.7 inverse femtobarns. The Z boson is identified via its decay
to a pair of muons. The measurement provides a precision test of quantum
chromodynamics over a large region of phase space. In addition, due to the
small experimental uncertainties in the measurement the data has the potential
to constrain the gluon parton distribution function in the kinematic regime
important for Higgs boson production via gluon fusion. The results agree with
the next-to-next-to-leading-order predictions computed with the FEWZ program.
The results are also compared to the commonly used leading-order MADGRAPH and
next-to-leading-order POWHEG generators.
