  A probabilistic reconstruction using machine-learning of the decay kinematics
of top-quark pairs produced in high-energy proton-proton collisions is
presented. A deep neural network whose core consists of a Bidirectional Long
Short-Term Memory (BLSTM) is trained to infer the four-momenta of the two top
quarks produced in the hard scattering process. The MadGraph5+Pythia8 Monte
Carlo event generator is used to create a sample of top-quark pairs decaying in
the $\mu$+jets channel, whose final-state objects are used to create the input
to the deep neural network. Distortions due to limited resolution of the
experimental apparatus are simulated with the Delphes3 fast detector simulator.
The level of agreement between the Monte Carlo predictions and the BLSTM for
kinematic distributions at parton level is comparable to that obtained using a
benchmark method that finds the jet permutation that minimizes an objective
function.
