IJS-FMF high-energy physics seminars

Florian Goertz: The Hierarchy Problem and the Top Yukawa

https://zoom.us/j/3601731049?pwd=bVNQRjUxU2ExZ0cveWcxYXNUUGdjZz09 (F1 tea room)


F1 tea room


The top-quark Yukawa coupling is one of the main driving forces of the hierarchy problem in the Higgs boson mass. We discuss its role in this context and present an alternative scheme to the conventional solutions with top partners, such as low-energy SUSY or composite Higgs. In fact, the lack of evidence for colored partners drives these models into more and more fine-tuned regions. Emphasizing that we have not measured the top-Higgs interactions at high scales yet, we envisage scenarios where this interaction is only approaching its sizable strength in the infra-red, but gets strongly suppressed at high energies - providing an alternative means to mitigate the top loop.
We first discuss possible effects via a modification of the running of the top Yukawa coupling. Then, we turn to models where the top Yukawa is generated at one-loop level and drops when crossing the mass threshold of new degrees of freedom. In either case, the top partners are replaced by new top-philic particles with strong interaction. Thus, a very different phenomenology, such as large top mass running and signals in four top final states, is introduced, which will be discussed. With the assistance of this mechanism, the solution to the hierarchy problem can be pushed to a (well-defined) higher scale, and a final test of naturalness might be deferred to a 100 TeV Collider, like the FCC.