  Azimuthal correlations in Z+jet production at large transverse momenta are
computed by matching Parton - Branching (PB) TMD parton distributions and
showers with NLO calculations via MCatNLO. The predictions are compared with
those for dijet production in the same kinematic range. The azimuthal
correlations $\Delta\phi$ between the Z boson and the leading jet are steeper
compared to those in dijet production at transverse momenta ${\cal O}(100)$
GeV, while they become similar for very high transverse momenta ${\cal
O}(1000)$ GeV. The different patterns of Z+jet and dijet azimuthal correlations
can be used to search for potential {\it factorization - breaking} effects in
the back-to-back region, which depend on the different color and spin structure
of the final states and their interferences with the initial states. In order
to investigate these effects experimentally, we propose to measure the ratio of
the distributions in $\Delta\phi$ for Z+jet - and multijet production at low
and at high transverse momenta, and compare the results to predictions obtained
assuming factorization. We examine the role of theoretical uncertainties by
performing variations of the factorization scale, renormalization scale and
matching scale. In particular, we present a comparative study of matching scale
uncertainties in the cases of PB-TMD and collinear parton showers.
