Title: Hidden Naturalness in the Light of Precision Cosmological Data

Speaker: Professor Yuhsin Tsai (University of Notre Dame)

Time: 10:00am, May 12, 2022

Location: ZOOM Meeting Link: https://notredame.zoom.us/j/2295072279?pwd=SkpqMlRDMDR5a01oeFZQSENvYXhkZz09

Abstract: Precision cosmological data can be used to study a class of "hidden naturalness" models that solve the Higgs hierarchy problem with the presence of invisible dark sector fields. Although these models only provide indirect signals to see at collider experiments, the presence of the dark sector particles can directly modify the cosmic microwave background (CMB) and large-scale structure (LSS) and leaves distinct cosmological signatures. In this talk, I will use the Mirror Twin Higgs (MTH) model, one of the most studied hidden naturalness solutions, to demonstrate how the CMB and LSS data constrain a hidden naturalness model. Additionally, I will show that besides addressing the Higgs hierarchy problem, the MTH model can relax tensions in the cosmological data by raising the Hubble constant H0 while reducing the matter fluctuations S8 simultaneously.