Small field polynomial inflation: reheating, radiative stability and lower bound
Abstract
We revisit the renormalizable polynomial inflection point model of inflation, focusing on the small field scenario which can be treated fully analytically. In particular, the running of the spectral index is predicted to be α = -1.43 × 10-3 +5.56 × 10-5(NCMB-65 ), which might be tested in future. We also analyze reheating through perturbative inflaton decays to either fermionic or bosonic final states via a trilinear coupling. The lower bound on the reheating temperature from successful Big Bang nucleosynthesis gives lower bounds for these couplings; on the other hand radiative stability of the inflaton potential leads to upper bounds. In combination this leads to a lower bound on the location ϕ0 of the near inflection point, ϕ0 > 3 · 10-5 in Planckian units. The Hubble parameter during inflation can be as low as Hinf~ 1 MeV, or as high as ~ 1010 GeV. Similarly, the reheating temperature can lie between its lower bound of ~ 4 MeV and about 4 · 108 (1011) GeV for fermionic (bosonic) inflaton decays. We finally speculate on the "prehistory" of the universe in this scenario, which might have included an epoch of eternal inflation.
- Publication:
-
Journal of Cosmology and Astroparticle Physics
- Pub Date:
- September 2021
- DOI:
- 10.1088/1475-7516/2021/09/012
- arXiv:
- arXiv:2104.03977
- Bibcode:
- 2021JCAP...09..012D
- Keywords:
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- inflation;
- particle physics - cosmology connection;
- physics of the early universe;
- High Energy Physics - Phenomenology;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- High Energy Physics - Theory
- E-Print:
- v2: typos corrected, references updated