Experimental Particle and Astro-Particle Physics Seminar

Stefanos Leontsinis (University of Zurich (CH))

Abstract: The post-Higgs discovery era has been characterized by an exciting physics programme targeting the investigation of the Higgs boson properties and couplings. Amongst the crucial yet-to-be answered questions in Particle Physics are the shape of the Higgs potential and the nature of the Higgs Yukawa couplings. 

Probing the Higgs self-coupling, which determines the shape of the Higgs potential and is directly connected to the electroweak symmetry breaking mechanism, is one of the most important goals of the High-Luminosity phase of the Large Hadron Collider (LHC) experiments. Higgs decay modes to light quarks, instead, are key to investigate the universality of the Yukawa couplings but they are very challenging or nearly impossible to detect with the current experiments at the LHC. A future e+e- collider is thus the perfect avenue to pursue this research.

The first part of this talk will describe the current results and the future projections of direct tests of the Higgs self-coupling via Higgs pair production with the ATLAS experiment at the LHC. The second part will be dedicated to the development of novel algorithms at future e+e- colliders for tagging jets originating from the hadronisation of strange quarks (strange-tagging) and the first application of such a strange-tagger to a direct Higgs to strange (h->ss) analysis with the ILD Concept Group at the International Liner Collider. The study includes a preliminary investigation of a Ring Imaging Cerenkov system (RICH) capable of maximising strange-tagging performance in future Higgs factory detectors.