Fake lepton studies in a search for heavy scalar in dilepton + jets final states with ATLAS detector
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Date
2021
Authors
Mashishi, Lehumo
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Abstract
The estimation of fake lepton background is presented for the physics beyond the
Standard Model search in the final state with a pair of different flavour opposite-sign
leptons, eµ, accompanied by at least two jets. The search uses the LHC full Run 2 data
recorded at a center-of-mass energy of 13 TeV collected with the ATLAS detector, with
the corresponding luminosity of 139 fb−1
. The search extends the Standard Model by
introducing the heavy scalar, H, and the additional Higgs-like scalar, S. One of the
challenges in most physics analysis is to estimate background processes that can enter
the signal region and be misidentified as the signal. This thesis focuses on the W+jets
background which enters the signal region. From the W+jets background process, there
is one real lepton from W and one fake which originates from the jet misidentified
as a lepton. The Monte Carlo simulation cannot be trusted for the estimation of
W+jets background as the rate of misidentification might not be well modelled. Hence
one has to develop the data-driven techniques for the W+jets estimation. In the
H → Sh → e
±µ
∓+jets analysis, the fake factor method is used for fake estimation.
Description
A dissertation submitted in fulfilment of the requirements for the degree of Master of Science to the Faculty of Science, School of Physics, University of the Witwatersrand, Johannesburg, 2021