Impact of SM parameters and of the vacua of the Higgs potential in gravitational waves detection

TL;DR

This paper investigates how the parameters of the Standard Model and the Higgs potential vacua influence the detectability of primordial gravitational waves generated during first-order phase transitions in extended scalar and fermion models, highlighting the importance of SM parameter precision.

Contribution

It is the first study to analyze the impact of SM parameter uncertainties on gravitational wave signals from phase transitions in singlet-extended models.

Findings

Certain model scenarios can produce detectable gravitational waves in planned experiments.

The detectability of GWs is highly sensitive to the Higgs and top quark parameters.

SM parameter variations significantly affect the strength of the gravitational wave spectrum.

Abstract

In this work we discuss two different phases of a complex singlet extension of the Standard Model (SM) together with an extension that also includes new fermion fields, in particular, a Majoron model equipped with an inverse seesaw mechanism. All considered scenarios contain a global $\mathrm{U}(1)$ symmetry and allow for first-order phase transitions while only two of them are strong enough to favour the detection of primordial gravitational waves (GWs) in planned experiments such as LISA. In particular, this is shown to be possible in the singlet extension with a non vanishing real VEV at zero temperature and also in the model with extra fermions. In the singlet extension with no additional fermions, the detection of GWs strongly depends on the $\mathrm{U}(1)$ symmetry breaking pattern of the scalar potential at zero temperature. We study for the first time the impact of the precision in the determination of the SM parameters on the strength of the GWs spectrum. It turns out that the variation of the SM parameters such as the Higgs boson mass and top quark Yukawa coupling in their allowed experimental ranges has a notable impact on GWs detectability prospects.