Unraveling The Physics Behind Modified Higgs Couplings -- LHC vs. a Higgs Factory

Understand

Strongly modified Higgs-photon-photon and Higgs-gluon-gluon couplings indicate new electroweak and color mediators, respectively, with a light mass and a significant coupling to the Higgs boson.

• We point out the Higgs boson could have a significant decay width into the mediators and propose uncovering the hidden new physics through such exotic decays, which can probe the Higgs coupling with the mediators directly.
• Focusing on the electroweak mediators, we study a simplified model using as an example final states with tau leptons and neutrinos.
• Because one of the mediators is off-shell and its decay products are extremely soft, it is challenging to make a discovery at the Large Hadron Collider.