Vacuum Stability, Perturbativity, EWPD and Higgs-to-diphoton in Type II Seesaw

TL;DR

This paper investigates the constraints on the type II seesaw model from vacuum stability, perturbativity, and electroweak precision data, analyzing their implications for Higgs couplings and triplet mass splitting.

Contribution

It provides new bounds on Higgs triplet couplings and mass splittings, and explores potential deviations in Higgs-to-diphoton decay rates within the model.

Findings

Higgs triplet couplings are tightly constrained by stability and perturbativity.

Electroweak precision data limit the triplet mass splitting to about 40 GeV.

Higgs-to-diphoton rate can significantly deviate from the Standard Model in certain parameter regions.

Abstract

We study constraints from perturbativity and vacuum stability as well as the EWPD in the type II seesaw model. As a result, we can put stringent limits on the Higgs triplet couplings depending on the cut-off scale. The EWPD tightly constrain the Higgs triplet mass splitting to be smaller than about 40 GeV. Analyzing the Higgs-to-diphoton rate in the allowed parameter region, we show how much it can deviate from the Standard Model prediction for specific parameter points.