  We study parton-branching solutions of QCD evolution equations and present a
method to construct both collinear and transverse momentum dependent (TMD)
parton densities from this approach. We work with next-to-leading-order (NLO)
accuracy in the strong coupling. Using the unitarity picture in terms of
resolvable and non-resolvable branchings, we analyze the role of the soft-gluon
resolution scale in the evolution equations. For longitudinal momentum
distributions, we find agreement of our numerical calculations with existing
evolution programs at the level of better than 1 percent over a range of five
orders of magnitude both in evolution scale and in longitudinal momentum
fraction. We make predictions for the evolution of transverse momentum
distributions. We perform fits to the high-precision deep inelastic scattering
(DIS) structure function measurements, and we present a set of NLO TMD
distributions based on the parton branching approach.
