Abstract: Since the discovery of the Higgs at the LHC, particle physics model building has been confronted with a severe conceptual challenge: the inferred values of the Higgs’ mass and self-coupling both appear to be fine-tuned. This not only poses the question what kind of new physics could explain such a behavior, but also undermines phenomenological efforts as acknowledging the possibility of fine-tuning oftentimes allows for the evasion of any experimental constraints. In the first half of my talk, I will review these fine-tunings and their implications more generally. In the second half, I will discuss a new class of explanations (including one concrete example) aimed at addressing these issues using ingredients that lie within range of realistic future experiments without already being excluded by LHC.

Bio: Thomas Steingasser obtained his PhD at LMU Munich under the supervision of Stefan Hofmann and Justin Khoury (UPenn). Following his PhD, he became a postdoctoral fellow at the Massachusetts Institute of Technology with a secondary affiliation at Harvard University working in the cosmology group of Alan Guth and David Kaiser. Since September 2025, he is a postdoctoral researcher at the Instituto de Física Teórica in Madrid, working with the groups of Belén Gavela and José-Ramon Espinosa. His research explores the intersection of particle physics, cosmology and more formal aspects of quantum field theory: Higgs physics and BSM model building, dark matter, various aspects of inflationary cosmology, vacuum stability and tunneling more generally.