The light quark Yukawa couplings are notoriously difficult to measure at the LHC. Current bounds and future projections for the HLLHC foresee that they can be constrained to be a factor of several hundred times their Standard Model value. The thesis aims to respond to the question on how large they actually can be in UV models. In order to address this question, models will be identified that generate deviations in light quark Yukawa couplings via dimensionsix effective operators at treelevel. A particular good choice not studied yet in depth in literature are models with vectorlike quarks. The list of possible models is finite and can hence been studied systematically, taking into account potential bounds from flavour physics, Higgs physics and electroweak precision tests. The latter in particular might set important bounds as models with vectorlike quarks typically generate also effective operators that modify the quark couplings to W and Z bosons. The thesis will also confront the concrete UV models with an effective field theory description.
How large can the light quark Yukawa couplings be?
ERDELYI, BARBARA ANNA
2023/2024
Abstract
The light quark Yukawa couplings are notoriously difficult to measure at the LHC. Current bounds and future projections for the HLLHC foresee that they can be constrained to be a factor of several hundred times their Standard Model value. The thesis aims to respond to the question on how large they actually can be in UV models. In order to address this question, models will be identified that generate deviations in light quark Yukawa couplings via dimensionsix effective operators at treelevel. A particular good choice not studied yet in depth in literature are models with vectorlike quarks. The list of possible models is finite and can hence been studied systematically, taking into account potential bounds from flavour physics, Higgs physics and electroweak precision tests. The latter in particular might set important bounds as models with vectorlike quarks typically generate also effective operators that modify the quark couplings to W and Z bosons. The thesis will also confront the concrete UV models with an effective field theory description.File  Dimensione  Formato  

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https://hdl.handle.net/20.500.12608/70106