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

TL;DR

This paper investigates the theoretical and experimental constraints on the Type II Seesaw model, focusing on vacuum stability, perturbativity, electroweak precision data, and Higgs decay rates, revealing potential enhancements in diphoton signals.

Contribution

It provides new bounds on Higgs triplet couplings and mass splittings, and explores the impact on Higgs-to-diphoton decay rates within the Type II Seesaw framework.

Findings

Higgs triplet couplings are tightly constrained depending on the cutoff scale.

Electroweak precision data limit the Higgs triplet mass splitting to less than 40 GeV.

Higgs-to-diphoton rate can be enhanced by up to 100% for certain parameter choices.

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 40 GeV. Analyzing the Higgs-to-diphoton rate in the allowed parameter region, we show a possible enhancement by up to 100 % and 50 % for the cut-off scale of 100 TeV and $10^{19}$ GeV, respectively, if the doubly charged Higgs boson mass is as low as 100 GeV.