  Reconstructing unstable heavy particles requires sophisticated techniques to
sift through the large number of possible permutations for assignment of
detector objects to the underlying partons. Anapproach based on a generalized
attention mechanism, symmetry preserving attention networks (SPA-NET), has been
previously applied to top quark pair decays at the Large Hadron Collider which
produce only hadronic jets. Here we extend the SPA-NET architecture to consider
multiple input object types, such as leptons, as well as global event features,
such as the missing transverse momentum. Inaddition, we provide regression and
classification outputs to supplement the parton assignment. We explore the
performance of the extended capability of SPA-NET in the context of
semi-leptonic decays of top quark pairs as well as top quark pairs produced in
association with a Higgs boson. We find significant improvements in the power
of three representative studies: a search for ttH, a measurement of the top
quark mass, and a search for a heavy Z' decaying to top quark pairs. We present
ablation studies to provide insight on what the network has learned in each
case.
