title: Reviving the thermal dark matter paradigm with long-lived particles
creator: Filimonova, Anastasiia
subject: ddc-530
subject: 530 Physics
description: The nature of dark matter is one of the most crucial open questions of modern fundamental physics. In this thesis, we aim to address this problem, focusing on minimal dark sector models that can be falsified with current experimental techniques. First, we study an effective theory of Higgs portal dark matter at the electroweak mass scale. We notice an almost unstudied mechanism of thermal dark matter production, the co-scattering mechanism, that is a general characteristic of models with extended dark sectors. Second, we connect the viable thermal dark sector theories with the corresponding collider signatures. We find that such sectors feature compressed mass spectra, resulting in long-lived mediators at colliders. We perform a comprehensive study of possible displaced signatures in the singlet-triplet Higgs portal model and find a remarkable potential of displaced searches in testing dark matter theories where traditional techniques fail. Finally, we extend our focus by exploring the prospects of long-lived particle searches at e+e− colliders. We predict the sensitivity of Belle II to displaced objects in rare meson decays, showing its ability to compete even with some of the long-baseline experiments.
date: 2020
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/28649/1/Thesis_Filimonova.pdf
identifier: DOI:10.11588/heidok.00028649
identifier: urn:nbn:de:bsz:16-heidok-286497
identifier:   Filimonova, Anastasiia  (2020) Reviving the thermal dark matter paradigm with long-lived particles.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/28649/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng