Top Quark Momentum Reconstruction Dataset

A set of Monte Carlo simulated events, for the evaluation of top quarks' (and their child particles') momentum reconstruction. The data is saved in HDF5 format, as sets of arrays with keys (as detailed below). There are 1.5M events, with approximately 700k in "train.h5", 200k in "valid.h5", 100k in "test.h5", and 500k in "test_large.h5".

There are two versions of the data, the difference between them being whether or not (fast) detector simulation was performed. Those with the detector simulation have the "_delphes" suffix in their filenames. Both versions are produced from the same set of generator-level events.

• 13 TeV center-of-mass energy, fully hadronic top quark decays, simulated with Pythia8.
  • Events are generated with leading top quark pT in [550,650] GeV.
  • Where applicable, detector simulation is done using Delphes, with the ATLAS detector card.
• Clustering of particles/objects is done using the anti-kT algorithm, with \(R=0.8\).
  • For the data without detector simulation, the inputs to clustering are the stable, visible final-state particles from Pythia8.
  • For the data with detector simulation, the inputs are calorimeter towers (`Towers`) from Delphes.
• Each entry corresponds with a single jet.
  • All jets are matched to a parton-level top quark within \(\Delta R =0.8\)
  • Jets are required to have \(|\eta| < 2, \; p_T > 15 \text{ GeV}\)

  • The 200 leading (highest \(p_T\)) jet constituent four-momenta are stored in Cartesian coordinates \((E,p_x,p_y,p_z)\), sorted by decreasing \(p_T\) and with with zero-padding for jets with fewer than 200 constituents. These are stored under the key `Pmu`. The number of non-zero jet constituents is stored under the key `Nobj`.

  • The jet four-momentum is stored in Cartesian coordinates and in cylindrical coordinates \((p_T,\eta,\phi,m)\) under keys `jet_Pmu` and `jet_Pmu_cyl`, respectively.

  • The truth (parton-level) four-momenta of the top quark, and the bottom quark and W-boson to which it decays, are stored in Cartesian coordinates in keys `truth_Pmu_0`, `truth_Pmu_1` and `truth_Pmu_2` respectively.

    • In addition, these are stored together under the key `truth_Pmu`, with the corresponding PDG codes stored under the key `truth_Pdg`.