Abstract
The goal of particle physics experiments is to reconstruct and measure the outgoing particles produced in proton–proton collisions to describe the hard scatter process. After an event is accepted by the ATLAS trigger systems to be recorded to disk, the objects of interest such as electrons, muons, and jets must be reconstructed from the low-level detector signals. These complex objects, meant to be representative of the true SM particle, are built from some of the low-level detector signals, such as muon spectrometer tracks or energy depositions in the electromagnetic or hadronic calorimeters. As the LHC is a hadron collider, the LHC tends to produce colored final states through the collisions of gluons. Many BSM physics models contain these hadronic objects which are crucial to reconstruct accurately, amidst the initial and final state radiation and multiple simultaneous proton–proton collisions. Once reconstructed, the measured properties of these objects may be calibrated to a particular energy scale.
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Notes
- 1.
Colloquially known as “reco jets,” short for reconstructed jets.
- 2.
Here, the noise is the expected noise σ noise in Eq. (5.3).
- 3.
Data-derived corrections are called in-situ corrections.
- 4.
The energy measured by the detectors is not the full energy of the particle that is being detected/measured.
- 5.
What this means is that the measured signal from the electromagnetic cells and hadronic cells are used with no other cell-level corrections.
- 6.
Colloquially called “LCTopo.”
- 7.
Colloquially called “EMTopo.”
- 8.
We bin in truth jet energy, rather than reco-jet energy to remove a dependence of the calibration on the reco-jet pT spectrum which includes detector-level effects that almost certainly introduce a bias.
- 9.
There are 80 total, but one of them is for a type of simulation not used in this thesis analysis and does not apply.
- 10.
There is a feature around 2.0 < |η| < 2.6 due to the non-closure uncertainty of the η-intercalibration.
- 11.
B-hadrons have a lifetime ∼1.5 ps (cτ ∼450 µm) compared to top quarks with a mean lifetime ∼10−25 s.
- 12.
The Run-2 algorithm performance is still undergoing study and will not be public in time for this thesis.
- 13.
Look at the name of the isolation variable to know the cone size.
- 14.
Look at the name of the isolation variable to know the cone size.
- 15.
Prompt electron candidates come from heavy-resonance decays such as W → eν e, Z → ee.
- 16.
Non-isolated candidates include electrons from photon conversion, from heavy-flavor hadron decays, and light hadrons mis-identified as electrons.
- 17.
Not to be confused with the New York Mets.
- 18.
A pun!.
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Stark, G. (2020). Event Reconstruction. In: The Search for Supersymmetry in Hadronic Final States Using Boosted Object Reconstruction. Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-030-34548-8_5
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