R2/Higgs inflation and the hierarchy problem

Preprint

We analyse Starobinsky inflation in the presence of the Brout Englert Higgs (BEH) boson with a non-minimal coupling to the Ricci scalar, R. The latter induces a coupling of the massive scaleron associated with the R² term to the BEH boson and this leads to a radiative correction to the BEH mass that must be fine tuned to keep the scalar light. For the case of R² driven inflation this requires a high level of fine tuning of order 1 part in 10⁸; for the case of Higgs inflation it is very much greater. We consider a scale invariant extension of the R²/Higgs model and find that for R² driven inflation but not for Higgs inflation the required fine tuning is significantly reduced to one part in 10^3–4. We consider the vacuum stability of the fine tuned model and its reheating and dilaton abundance after inflation. We also discuss possible gravitational wave signals associated with the model and the constraint on the mass of scalar or fermion dark matter candidates if they are produced by the gravitational couplings of the scalaron.

Authors: Ferreira, PG; Hill, CT; Noller, J; Ross, GG

• Publication status: Published
• Peer review status: Not peer reviewed
• Preprint server: arXiv
• Publication date: 2021-08-13
• DOI: 10.48550/arxiv.2108.06095
• Language: English