Dr. Sarah Williams, Cambridge University

"The quest for dark matter at the LHC: new results from electroweak supersymmetry searches using the ATLAS detector"

Abstract: The discovery of the Higgs Boson by the ATLAS and CMS collaborations at CERN marked a tremendous milestone in High Energy Physics: the experimental competition of the Standard Model of Particle Physics. This in turn confirmed the need to address some of the shortcomings of the theory, the lack of a viable candidate for Dark Matter being one of them. This elusive substance, which we now understand makes up around a quarter of the mass-energy content of the universe, has been studied through its gravitational effects in our universe, but has eluded collider, direct and indirect searches to date. It has thus been a key target for searches for new physics at the Large Hadron Collider (LHC) throughout its second data-taking run. This seminar will discuss some of the latest results from the ATLAS experiment with a focus on searches for the electroweak production of supersymmetric particles. Supersymmetry (SUSY) is a popular beyond-the-Standard Model (BSM) theory that can address several shortcomings of the SM. The electroweak sector, comprising gauginos and sleptons, contains the particles most relevent to the dark matter mystery, has a rich phenomenology that varies strongly as a function of the SUSY parameters, meaning that we have only really hit the tip of the iceberg in terms of the parameter space to be explored at the LHC. The wider picture of DM searches at the LHC will also be discussed, along with prospects for run III.