TY  - GEN
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/25147/
N2  - In the context of models with modified Higgs sectors, we examine different possible causes for a systematic absence of new physics from current searches at the Large Hadron Collider (LHC). First, having in mind the lack of clear signs for supersymmetry, we consider theories based on classical scale invariance as an alternative approach towards addressing the gauge hierarchy problem. Within the aforementioned framework, we present a systematic analysis of simple Standard Model (SM) extensions. As a result, we identify the minimal model, which allows for radiative electroweak symmetry breaking, is consistent with all current experimental constraints and does not reintroduce any fine-tuning issues. Next, given that very light scalar particles as predicted by several well-motivated beyond-the-SM theories have not yet been detected either, we propose a novel search strategy based on exotic Higgs decays into three of these light scalars. We show that said processes can be abundant enough to be observable at the LHC or future lepton colliders in exciting new signatures containing six SM fermions in the final state. In particular, we demonstrate the three-body channel's capabilities in probing scenarios which are inaccessible to existing searches exclusively relying on the related two-body Higgs decay. Our last study is motivated by the fact that new physics may manifest itself only through effects which are out of the LHC's reach due to the large amounts of hadronic background. As an example, we consider quark-flavor-violating Higgs decays involving bottom quarks and evaluate the expected sensitivity of direct searches at the proposed International Linear Collider (ILC). In doing so, we identify hadronic SM Higgs decays with mistagged jets as the dominant background processes and find that a dedicated analysis is anticipated to explore branching ratios down to the per-mill level.
A1  - Helmboldt, Alexander
KW  - Neue Physik
KW  -  klassische Skaleninvarianz
KW  -  exotische Higgs Zerfälle
Y1  - 2018///
ID  - heidok25147
AV  - public
TI  - New insights into modified scalar sectors and exotic Higgs decays
ER  -