HEP Weekly Seminar: Universal Seesaw mediated by vector-like families within an extended 2HDM as a possible explanation for the electron and muon anomalous magnetic moments

Wednesday 6 Jan 2021, 14:30 → 15:30 America/Santiago

Abstract:

We study the origin of Yukawa coupling constants in an extended 2 Higgs doublet model (2HDM) in which the standard Yukawa interactions are forbidden to arise due to gauged U(1)^\prime quantum numbers but Yukawa interactions with vector-like families are allowed. In this model, we explain the relative smallness of Yukawa constants of quarks and leptons depends on the mass of fourth and fifth vector-like families, while the order of Yukawa constant at higher energy scale as high as TeV scale remains ideally order of unity. Therefore, this model can explain the hierarchical structure which appears in the Standard Model. Within this model, we focused on the W exchange at one-loop level to explain both anomalies simultaneously, while being consistent on the \mu \rightarrow e \gamma constraint, and arrived a conclusion that impact of the W exchange for the anomalies is quite negligible, so it requires another approach. Then we come up with the scalar exchange at one-loop level and show it is possible to explain both anomalies within 1\sigma constraint by numerical arguments, while keeping mixing of charged leptons from arising. We listed some benchmarked numerical results for both anomalies, which tells that this model is quite flexible to predict mass of the multiple scalars that appear in this model.

 

PhD. Candidate Huchan Lee (University of Southampton)