Standard Model Higgs inflation supplemented by minimal dark matter

TL;DR

This paper revisits Higgs inflation within the Standard Model extended by minimal dark matter, analyzing its stability, reheating, and cosmological predictions, resulting in specific values for the spectral index and tensor-to-scalar ratio.

Contribution

It demonstrates that minimal dark matter extension can support Higgs inflation with stable potential and robust cosmological predictions, accounting for updated parameters and reheating dynamics.

Findings

Spectral index n_s=0.9672

Tensor-to-scalar ratio r=0.0031

Model predictions are insensitive to right-handed neutrino mass variations

Abstract

Renormalisation group analysis with the present measurements of the top quark mass $m_t = 172.69\pm 0.30$ GeV indicates that the Standard Model (SM) Higgs potential becomes unstable at energy scales $\sim 10^{10}$ GeV. This may be interpreted as hinting at new particles at high energy. The minimal extension of the SM that can avoid this instability while leaving the SM Higgs as the sole scalar particle of the theory is obtained by adding suitable fermions to the SM. These fermions are good dark matter candidates and the model is known as the minimal dark matter model. We revisit the inflationary scenario based on the minimal dark matter model, taking into account updated parameter constraints and recent understanding of reheating dynamics. We explore the model with different values of the right-handed neutrino mass and find that the cosmological prediction is insensitive to such details. We obtained a spectral index of the cosmic microwave background $n_s=0.9672$ and a tensor-to-scalar ratio $r=0.0031$ as a robust prediction of this scenario.