Particle production during inflation: Observational constraints and signatures
- Canadian Institute for Theoretical Astrophysics, University of Toronto, McLennan Physical Laboratories, 60 St. George Street, Toronto, Ontario, M5S 3H8 (Canada)
In a variety of inflation models the motion of the inflaton may trigger the production of some noninflaton particles during inflation, for example, via parametric resonance or a phase transition. Particle production during inflation leads to observables in the cosmological fluctuations, such as features in the primordial power spectrum and also non-Gaussianities. Here we focus on a prototype scenario with inflaton, {phi}, and isoinflaton, {chi}, fields interacting during inflation via the coupling g{sup 2}({phi}-{phi}{sub 0}){sup 2}{chi}{sup 2}. Since several previous investigations have hinted at the presence of localized 'glitches' in the observed primordial power spectrum, which are inconsistent with the simplest power-law model, it is interesting to determine the extent to which such anomalies can be explained by this simple and microscopically well-motivated inflation model. Our prototype scenario predicts a bumplike feature in the primordial power spectrum, rather than an oscillatory 'ringing' pattern as has previously been assumed. We discuss the observational constraints on such features using a variety of cosmological data sets. We find that bumps with amplitudes as large as O(10%) of the usual scale-invariant fluctuations from inflation, corresponding to g{sup 2}{approx}0.01, are allowed on scales relevant for cosmic microwave background experiments. Our results imply an upper limit on the coupling g{sup 2} (for a given {phi}{sub 0}) which is crucial for assessing the detectability of the non-Gaussianity produced by inflationary particle production. We also discuss more complicated features that result from superposing multiple instances of particle production. Finally, we point to a number of microscopic realizations of this scenario in string theory and supersymmetry and discuss the implications of our constraints for the popular brane/axion monodromy inflation models.
- OSTI ID:
- 21316608
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 80, Issue 12; Other Information: DOI: 10.1103/PhysRevD.80.126018; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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