A search for the Higgs boson decaying to e+e− using data from the ATLAS detector

Abstract

Aim: The aim of this thesis is to examine the decay of the Higgs boson to an electron-positron pair, H → e+ e− using the invariant mass of the leading and sub-leading electrons. Method: An invariant mass reconstruction model, with two different types of cuts, was developed by looking at a Z → e+ e− Monte Carlo sample and then real data. The model was then been run on real data from the LHC. Findings: By running the model against real data, it is found that the model correctly identifies the presence of Z bosons and also confirms that Higgs bosons are not present in the samples that the model is investigating. This model got limits for the effective cross sections of the H → e+ e− decay. For the 2018 sample with a pT > 20 GeV cut the effective cross section limit was found to be σ_eff < 99.04 fb and for the 2016 sample with Loose electrons the effective cross section limit was found to be σ_eff < 24.23 fb.