Heavy neutrino impact on the triple Higgs coupling

Understand

We present the first calculation of the one-loop corrections to the triple Higgs coupling in the framework of a simplified 3+1 Dirac neutrino model, that is three light neutrinos plus one heavy neutrino embedded in the Standard Model (SM).

• The triple Higgs coupling is a key parameter of the scalar potential triggering the electroweak symmetry-breaking mechanism in the SM.
• The impact of the heavy neutrino can be as large as $+20\%$ to $+30\%$ for parameter points allowed by the current experimental constraints depending on the tightness of the perturbative bound.
• This can be probed at the high-luminosity LHC, at future electron-positron colliders and at the Future Circular Collider in hadron-hadron mode, an envisioned 100 TeV $pp$ machine.