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Title: Resonant particle production during inflation: a full analytical study

Abstract

We revisit the study of the phenomenology associated to a burst of particle production of a field whose mass is controlled by the inflaton field and vanishes at one given instance during inflation. This generates a bump in the correlators of the primordial scalar curvature. We provide a unified formalism to compute various effects that have been obtained in the literature and confirm that the dominant effects are due to the rescattering of the produced particles on the inflaton condensate. We improve over existing results (based on numerical fits) by providing exact analytic expressions for the shape and height of the bump, both in the power spectrum and the equilateral bispectrum. We then study the regime of validity of the perturbative computations of this signature. Finally, we extend these computations to the case of a burst of particle production in a sector coupled only gravitationally to the inflaton.

Authors:
;  [1];  [2]
  1. School of Physics and Astronomy, University of Minnesota, 116 Church Street S.E., Minneapolis, MN 55455 (United States)
  2. Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts, 1126 Lederle Graduate Research Tower (LGRT), Amherst, MA 01003 (United States)
Publication Date:
OSTI Identifier:
22676190
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 05; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CALCULATION METHODS; CONDENSATES; INFLATIONARY UNIVERSE; INFLATONS; MASS; PARTICLE PRODUCTION; RESCATTERING; SPECTRA

Citation Formats

Pearce, Lauren, Peloso, Marco, and Sorbo, Lorenzo, E-mail: lpearce@physics.umn.edu, E-mail: peloso@physics.umn.edu, E-mail: sorbo@physics.umass.edu. Resonant particle production during inflation: a full analytical study. United States: N. p., 2017. Web. doi:10.1088/1475-7516/2017/05/054.
Pearce, Lauren, Peloso, Marco, & Sorbo, Lorenzo, E-mail: lpearce@physics.umn.edu, E-mail: peloso@physics.umn.edu, E-mail: sorbo@physics.umass.edu. Resonant particle production during inflation: a full analytical study. United States. doi:10.1088/1475-7516/2017/05/054.
Pearce, Lauren, Peloso, Marco, and Sorbo, Lorenzo, E-mail: lpearce@physics.umn.edu, E-mail: peloso@physics.umn.edu, E-mail: sorbo@physics.umass.edu. Mon . "Resonant particle production during inflation: a full analytical study". United States. doi:10.1088/1475-7516/2017/05/054.
@article{osti_22676190,
title = {Resonant particle production during inflation: a full analytical study},
author = {Pearce, Lauren and Peloso, Marco and Sorbo, Lorenzo, E-mail: lpearce@physics.umn.edu, E-mail: peloso@physics.umn.edu, E-mail: sorbo@physics.umass.edu},
abstractNote = {We revisit the study of the phenomenology associated to a burst of particle production of a field whose mass is controlled by the inflaton field and vanishes at one given instance during inflation. This generates a bump in the correlators of the primordial scalar curvature. We provide a unified formalism to compute various effects that have been obtained in the literature and confirm that the dominant effects are due to the rescattering of the produced particles on the inflaton condensate. We improve over existing results (based on numerical fits) by providing exact analytic expressions for the shape and height of the bump, both in the power spectrum and the equilateral bispectrum. We then study the regime of validity of the perturbative computations of this signature. Finally, we extend these computations to the case of a burst of particle production in a sector coupled only gravitationally to the inflaton.},
doi = {10.1088/1475-7516/2017/05/054},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 05,
volume = 2017,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}
  • We analyze the limits on resonant particle production during inflation based upon the power spectrum of fluctuations in matter and the cosmic microwave background. We show that such a model is consistent with features observed in the matter power spectrum deduced from galaxy surveys and damped Lyman-{alpha} systems at high redshift. It also provides an alternative explanation for the excess power observed in the power spectrum of the cosmic microwave background fluctuations in the range of 1000<l<3500. For our best-fit models, epochs of resonant particle creation reenter the horizon at wave numbers of k{sub *}{approx}0.4 and/or 0.2 (h Mpc{sup -1}).more » The amplitude and location of these features correspond to the creation of fermion species of mass {approx}1-2 M{sub pl} during inflation with a coupling constant between the inflaton field and the created fermion species of near unity. Although the evidence is marginal, if this interpretation is correct, this could be one of the first observational hints of new physics at the Planck-scale.« less
  • The phenomenon of the resonant production of particles after inflation has received much attention in the past few years. In a new application of the resonant production of particles, we consider the effect of a resonance during inflation. We show that if the inflaton is coupled to a massive particle, resonant production of the particle during inflation modifies the evolution of the inflaton, and may leave an imprint in the form of sharp features in the primordial power spectrum. Precision measurements of microwave background anisotropies and large-scale structure surveys could be sensitive to the features, and probe the spectrum ofmore » particles as massive as the Planck scale. (c) 2000 The American Physical Society.« less
  • The impact of particle production during inflation on the primordial curvature perturbation spectrum is investigated both analytically and numerically. We obtain an oscillatory behavior on small scales, while on large scales the spectrum is unaffected. The amplitude of the oscillations is proportional to the number of coupled fields, their mass, and the square of the coupling constant. The oscillations are due to a discontinuity in the second time derivative of the inflaton, arising from a temporary violation of the slow-roll conditions. A similar effect on the power spectrum should be produced also in other inflationary models where the slow-roll conditionsmore » are temporarily violated.« less
  • 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 themore » 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.« less