  A factorization formalism for jet processes involving massive colored
particles such as the top quark is developed, extending earlier results for the
massless case. The factorization of soft emissions from the underlying hard
process is implemented in an effective field theory framework, which forms the
basis for the resummation of large logarithms. The renormalization group
evolution giving rise to non-global logarithms is implemented into a parton
shower code in the large-$N_c$ limit. After a comparison of the massive and
massless radiations patterns, the cross section for $t\bar{t}$ production with
a veto on additional central jet activity is computed, taking into account
radiation both from the production and the decay of the top quarks. The
resummation of the leading logarithms leads to an improved description of ATLAS
measurements at $\sqrt{s}=7\,{\rm TeV}$.
