Dileptonic ttbar Neutrino Regression Dataset

Two sets of MC simulated events for the training/evaluation of neutrino regression models. The two datasets use different matrix element generators (MadGraph and Pythia).

• The nominal (Magraph) dataset contains 940605 events split across 4 files for training and one file containing 75496 events for final evaluation
• The alternative (Pythia) dataset contains 1248315 events split across 9 files for training and one file containing 138128 events for final evaluation.

Simulation Details

• All events are generated from simulated proton-proton collisions at a center-of-mass energy of 13 TeV.
• The mass of the top quark is set to 173 GeV.
• The nominal dataset has MadGraph (v3.1.0) for ME calculation and Pythia8 (v8.243) for the shower, while the alternative dataset uses Pythia8 (v8.307) for both ME and shower.
• Both samples are interfaced to Delphes (v3.4.2) for detector simulation with a parametrization that mimics the response of the ATLAS detector.

Event Reconstruction and Selection

• Jets are reconstructed using energy-flow objects and the anti-kt algorithm with R=0.4.
• Jet b-tagging corresponding to an inclusive signal efficiency of 70%.
• At least two jets with pT > 25 GeV in the range |eta|<2.5 are required.
• Exactly two reconstructed electrons or muons with pT > 15 GeV in the range |eta|<2.5 is required.

File Contents

Each HDF file contains the “delphes” table which holds multiple arrays and structured arrays.

The reconstructed information includes:

• MET: The missing transverse momentum of the event (stored using polar cords)
  • Keys: MET, phi
• leptons: The single reconstructed lepton in the event:
  • Keys: pt, eta, phi, energy, charge, type
• jets: A zero padded table of the leading 10 jets in the event
  • Keys: pt, eta, phi, energy, is_tagged
• njets: Numpy array holding the number of reconstructed jets in the event
• nbjets: Numpy array holding the number of b-tagged jets

The truth/generator level information includes:

• neutrinos: Truth level information of the single neutrino in the event
  • Keys: PDGID, pt, eta, phi, mass
• truth_quarks: Table of information for the two b-quarks in the event
  • Keys: PDGID, pt, eta, phi, mass
• truth_particles: Table of information of all truth level particles in the event
  • Keys: PDGID, pt, eta, phi, mass
• jets_indices: A numpy array containing the identity of each of the jets in the reconstructed jet array (above)
  • 0 = b-jet, 1 = anti b-jet, -1 = other