Daniel Joseph Antrim (UCI) “It Takes Two to Lambda: A New Dilepton Channel for the Search for Higgs Boson Pairs and a Pair of New Small Wheels for the Upgrade of the ATLAS Detector at CERN”

Abstract: 

The rich program of study opened up by the discovery of a 125 GeV boson in 2012 so far leads us to consider this particle to be the Higgs boson as predicted by the Standard Model (SM) of particle physics, the particle famously responsible for providing elementary particles their masses. To be sure that this is the case, the last-remaining fundamental parameter of the SM — the Higgs self-coupling parameter, “\lambda” — will have to be measured and checked for consistency with SM-prediction. In the SM, the parameter \lambda gives structure to the Higgs vacuum and is therefore fundamental to our understanding of electroweak physics and symmetry breaking that is paramount to our understanding of the Universe. Measurement of \lambda at the LHC will proceed via the study of ultra-rare pp collision events in which Higgs boson pairs (HH) are produced. If the LHC is to have a chance at making meaningful statements about \lambda, all avenues of study of HH must be sought out. In this talk I will therefore discuss a promising brand new channel in the search for Higgs boson pairs that I have developed and introduced over the past several years using the ATLAS detector at CERN. Additionally, with the foreseen increases in pp collision intensities over the next decades, the ATLAS detector will have to be upgraded if the physics program is to remain successful. This is especially true if we wish to have any hope of observing HH events. With this in mind, I will also touch upon my involvement in the on-going upgrade of the forward muon system of the ATLAS detector, the so-called “New Small Wheel” (NSW) Upgrade, which comprises an upgrade of over 60% of ATLAS’ muon spectrometer coverage as well as being the largest on-going upgrade of any of the LHC experiments.