Inflection-Point B−L Higgs Inflation

Abstract

Inflection-point inflation is an interesting possibility to realize a successful slow-roll inflation when inflation is driven by a single scalar field with its initial value below the Planck mass (ϕₗ≲Mₚₗ). In order for a renormalization group (RG) improved effective λϕ⁴ potential to develop an inflection point, the quartic coupling λ(ϕ) must exhibit a minimum with an almost vanishing value in its RG evolution, namely λ(ϕₗ)≃0 and βλ(ϕₗ)≃0, where βλ is the beta function of the quartic coupling. As an example, we consider the minimal gauged B−L extended Standard Model at the TeV scale, where we identify the B−L Higgs field as the inflaton field. For a successful inflection-point inflation, which is consistent with the current cosmological observations, the mass ratios among the Z′ gauge boson, the right-handed neutrinos and the B−L Higgs boson are fixed. Our scenario can be tested in the future collider experiments such as the high-luminosity LHC and the SHiP experiments. In addition, the inflection-point inflation provides a unique prediction for the running of the spectral index α ≃ −2.7 × 10⁻³(60/N)² (N is the e-folding number), which can be tested in the near future.