Birgit Stapf, promovenda aan het Nikhef, verdedigt haar proefschrift vrijdag 19 maart 2021 online aan de Universiteit van Amsterdam.
“Heavy Higgs Hunting – A search for a heavy Higgs boson decaying to a pair of Z bosons with the ATLAS detector “
Our current best understanding of the world of elementary particles is summarized in the Standard Model (SM). Although the discovery of the Higgs boson at the Large Hadron Collider (LHC) in 2012 was a milestone for the SM, it is not the end of all questions, but a new beginning. There are many observations the SM is unable to explain, such as the nature of dark matter and gravity. Answers to such questions come in the form of Beyond the Standard Model theories, many of which predict the existence of more than one Higgs boson. Motivated by this, a search for an additional heavy Higgs boson decaying to a pair of Z bosons is presented in this thesis.
The search is based on proton-proton collision LHC data collected by the ATLAS experiment throughout 2015-2018, with a centre-of-mass energy of 13 TeV.
Different scenarios for the heavy Higgs mass within the range from 200 GeV to 2 TeV are probed and a narrow-width and large-width analysis are performed.
The main focus of this thesis is the search in the H→ZZ→llvv channel, where one Z boson decays to a pair of electrons or muons and the other to two neutrinos. To increase sensitivity, the results of the llvv search are combined with those of a similar search in the llll channel.
No evidence for a heavy Higgs boson is found in the data. Exclusion limits are set on the respective production cross-sections of the various Higgs boson hypotheses.
“Heavy Higgs Hunting – A search for a heavy Higgs boson decaying to a pair of Z bosons with the ATLAS detector ” (pdf)
De promotie zal online te volgen zijn op het youtubekanaal van de Universiteit van Amsterdam:
Promotor: prof. dr. W. Verkerke
Co-promotor: dr. P. Kluit
contact: Birgit Stapf