Lepton-Jet Background
Advisor(s)
Dr. Peter Dong; Illinois Mathematics and Science Academy
Discipline
Physical Science
Start Date
21-4-2021 9:10 AM
End Date
21-4-2021 9:25 AM
Abstract
We analyzed the contribution of potential backgrounds for lepton-jets created from the decay of dark photons. Lepton-jets are identified by the presence of at least two collimated leptons, but these jets may have significant pion contamination. Therefore, the primary lepton-jet backgrounds come from Standard Model (SM) processes that happen to contain two leptons that are close enough to fake a lepton-jet. We used the PYTHIA 8 Monte Carlo generator to generate SM events (with no lepton-jets) involving three processes most likely to result in lepton-jet fakes (based on a previous CMS dilepton study): b-bbar → leptons, ZZ → leptons, and J-Ψ decay. These events were analyzed with our lepton-jet algorithm to determine the fake rates for each process. We found bbbar events to contribute the most to the background, followed by ZZ events, with J-Ψ decay being largely insignificant.
Lepton-Jet Background
We analyzed the contribution of potential backgrounds for lepton-jets created from the decay of dark photons. Lepton-jets are identified by the presence of at least two collimated leptons, but these jets may have significant pion contamination. Therefore, the primary lepton-jet backgrounds come from Standard Model (SM) processes that happen to contain two leptons that are close enough to fake a lepton-jet. We used the PYTHIA 8 Monte Carlo generator to generate SM events (with no lepton-jets) involving three processes most likely to result in lepton-jet fakes (based on a previous CMS dilepton study): b-bbar → leptons, ZZ → leptons, and J-Ψ decay. These events were analyzed with our lepton-jet algorithm to determine the fake rates for each process. We found bbbar events to contribute the most to the background, followed by ZZ events, with J-Ψ decay being largely insignificant.