Gravitational inflaton decay and the hierarchy problem

Abstract

We study implications of the large-N species solution to the hierarchy problem, proposed by G. Dvali, for reheating of the universe after inflation. Dvali's proposal contains additional N~10^{32} Z_2-conserved quantum fields beyond the Standard Model particles with mass ~1 TeV, which weaken gravity by a factor of 1/N, and thus explain the hierarchy between the Plank scale and the electroweak scale. We show that, in this scenario, the decay rates of inflaton fields through gravitational decay channels are enhanced by a factor of N, and thus they decay into N species of the quantum fields very efficiently, in the limit that quantum gravity effects are unimportant for the gravitational decay rate. In order not to over-reheat the universe, inflaton mass, vacuum expectation value of inflaton, or non-minimal gravitational coupling should be tightly fine-tuned. Our conclusion holds even when the gravitational decay is prohibited by some symmetry of the theory; the universe may still be over-reheated via annihilation of inflatons, if the number density of inflaton quanta is greater than the critical value.

6 pages, submitted to PRD, (v2) references added, (v3) revised to have inflaton quanta canonically normalized

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Cited by in corpus (17)

• Gravitational Particle Production in Oscillating Background and Its Cosmological Implications
• Gravitational waves from an early matter era
• Cosmology With Many Light Scalar Fields: Stochastic Inflation and Loop Corrections
• Reheating the Universe After Multi-Field Inflation
• Phenomenology of 10^32 Dark Sectors
• Non-Minimally Gravity-Coupled Inflationary Models
• Gravitational wave signals and cosmological consequences of gravitational reheating
• Dark Matter via Many Copies of the Standard Model
• Compact Dark Matter Objects via $N$ Dark Sectors
• Higgsflation at the GUT scale in a Higgsless Universe
• Rate of gravitational inflaton decay via gauge trace anomaly
• No quasi-stable scalaron lump forms after $R^2$ inflation
• Multi-field formulation of gravitational particle production after inflation
• Unified cosmology with Non-minimally coupled scalar-tensor theory of gravity
• Strong CP Problem with 10^{32} Standard Model Copies
• Curvaton scenarios with inflaton decays into curvatons
• A Note on Gravitational Particle Production in Supergravity