High Energy Physics Seminars

Searches for long-lived particles (LLPs) with macroscopic decay lengths are a rapidly expanding frontier at the LHC and other collider experiments. Still, many gaps remain in the current search program, in particular for light LLPs with masses at the GeV or sub-GeV scale and with decay lengths on the order of meters. In this talk, I will illustrate approaches to filling this gap by discussing two models of light LLPs that naturally fall into this decay length regime and their signals at the LHC and at Belle II. First, I will discuss a theory with a heavy vectorlike lepton that decays into pseudoscalar and a tau lepton, and focus on signals of long-lived pseudoscalars in the muon chambers of CMS or ATLAS. Second, I will illustrate the sensitivity of Belle II to light LLPs with meter-scale decay lengths using displaced vertex signals from strongly interacting dark sectors as an example.