000003632 001__ 3632
000003632 005__ 20230530190038.0
000003632 037__ $$aBELLE2-MTHESIS-2023-030
000003632 041__ $$aeng
000003632 100__ $$aTim Tueschen 
000003632 245__ $$aDark shower investigations at Belle II for strongly interacting dark sectors
000003632 260__ $$aVancouver, BC, Canada$$bUniversithy of British Columbia$$c2022
000003632 300__ $$a72
000003632 500__ $$aPresented on 18 10 2022
000003632 502__ $$aMSc$$bVancouver, BC, Canada, University of British Columbia$$c2022
000003632 520__ $$aThe so far unresolved question of the nature of dark matter has led to the development of a multitude of particle physics models that all meet current experimental and theoretical constraints, but differ greatly in the experimental signatures they predict. One idea that has been gaining popularity is that there could be a whole family of dark matter particles, forming a so called ’dark sector’ that interacts only very feebly with regular matter. In this thesis we investigate a hypothetical strongly interacting dark sector that confines at the GeV scale, which results in the production of a shower of dark sector mesons, including a long-lived neutral particle. This would result in a displaced vertex signature at e+e− colliders such as the Belle II experiment. We provide a brief overview of current evidence for Dark Matter and existing constraints to motivate the choice of a QCD–like dark sector with a dark photon mediator, as well as a detailed description of the Belle II detector which has an excellent sensitivity to displaced vertex signatures. After briefly summarizing the model, we describe the general search strategy, examine possible sources of background, and test the feasibility of a zero-background analysis. We find that, while not all signatures can be investigated in the zero-background case, the model offers a large parameter space that can be well investigated at Belle II with currently available data.
000003632 700__ $$aJanis McKenna$$edir.
000003632 8560_ $$fjanis@physics.ubc.ca
000003632 8564_ $$uhttps://docs.belle2.org/record/3632/files/BELLE2-MTHESIS-2023-030.pdf
000003632 980__ $$aTHESIS