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Title: Productive interactions: heavy particles and non-Gaussianity

Abstract

We analyze the shape and amplitude of oscillatory features in the primordial power spectrum and non-Gaussianity induced by periodic production of heavy degrees of freedom coupled to the inflaton Φ. We find that non-adiabatic production of particles can contribute effects which are detectable or constrainable using cosmological data even if their time-dependent masses are always heavier than the scale Φ 1/2, much larger than the Hubble scale. This provides a new role for UV completion, consistent with the criteria from effective field theory for when heavy fields cannot be integrated out. This analysis is motivated in part by the structure of axion monodromy, and leads to an additional oscillatory signature in a subset of its parameter space. At the level of a quantum field theory model that we analyze in detail, the effect arises consistently with radiative stability for an interesting window of couplings up to of order ≲ 1. The amplitude of the bispectrum and higher-point functions can be larger than that for Resonant Non-Gaussianity, and its signal/noise may be comparable to that of the corresponding oscillations in the power spectrum (and even somewhat larger within a controlled regime of parameters). Its shape is distinct from previously analyzed templates,more » but was partly motivated by the oscillatory equilateral searches performed recently by the Planck collaboration. As a result, we also make some general comments about the challenges involved in making a systematic study of primordial non-Gaussianity.« less

Authors:
 [1];  [2];  [3];  [3]
  1. The Univ. of Texas at Austin, Austin, TX (United States)
  2. Institute for Advanced Study, Princeton, NJ (United States)
  3. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Kavli Institute for Particle Astrophysics and Cosmology, Stanford, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1417667
Alternate Identifier(s):
OSTI ID: 1491157
Grant/Contract Number:  
[AC02-76SF00515; SC0008078]
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
[ Journal Volume: 2017; Journal Issue: 10]; Journal ID: ISSN 1475-7516
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; inflation; non-gaussianity; physics of the early universe

Citation Formats

Flauger, Raphael, Mirbabayi, Mehrdad, Senatore, Leonardo, and Silverstein, Eva. Productive interactions: heavy particles and non-Gaussianity. United States: N. p., 2017. Web. doi:10.1088/1475-7516/2017/10/058.
Flauger, Raphael, Mirbabayi, Mehrdad, Senatore, Leonardo, & Silverstein, Eva. Productive interactions: heavy particles and non-Gaussianity. United States. doi:10.1088/1475-7516/2017/10/058.
Flauger, Raphael, Mirbabayi, Mehrdad, Senatore, Leonardo, and Silverstein, Eva. Tue . "Productive interactions: heavy particles and non-Gaussianity". United States. doi:10.1088/1475-7516/2017/10/058. https://www.osti.gov/servlets/purl/1417667.
@article{osti_1417667,
title = {Productive interactions: heavy particles and non-Gaussianity},
author = {Flauger, Raphael and Mirbabayi, Mehrdad and Senatore, Leonardo and Silverstein, Eva},
abstractNote = {We analyze the shape and amplitude of oscillatory features in the primordial power spectrum and non-Gaussianity induced by periodic production of heavy degrees of freedom coupled to the inflaton Φ. We find that non-adiabatic production of particles can contribute effects which are detectable or constrainable using cosmological data even if their time-dependent masses are always heavier than the scale Φ1/2, much larger than the Hubble scale. This provides a new role for UV completion, consistent with the criteria from effective field theory for when heavy fields cannot be integrated out. This analysis is motivated in part by the structure of axion monodromy, and leads to an additional oscillatory signature in a subset of its parameter space. At the level of a quantum field theory model that we analyze in detail, the effect arises consistently with radiative stability for an interesting window of couplings up to of order ≲ 1. The amplitude of the bispectrum and higher-point functions can be larger than that for Resonant Non-Gaussianity, and its signal/noise may be comparable to that of the corresponding oscillations in the power spectrum (and even somewhat larger within a controlled regime of parameters). Its shape is distinct from previously analyzed templates, but was partly motivated by the oscillatory equilateral searches performed recently by the Planck collaboration. As a result, we also make some general comments about the challenges involved in making a systematic study of primordial non-Gaussianity.},
doi = {10.1088/1475-7516/2017/10/058},
journal = {Journal of Cosmology and Astroparticle Physics},
number = [10],
volume = [2017],
place = {United States},
year = {2017},
month = {10}
}

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Figures / Tables:

Figure 1 Figure 1: Pictorial representation of our findings: in an inflationary theory with an approximate continuous shift symmetry for the inflaton, only particles that are not much heavier than the Hubble scale H are relevant for the dynamics of the fluctuations. However, as we will see, if the continuous shift symmetrymore » is broken, e.g. to a discrete shift symmetry, heavier particles can become relevant as depicted on the right. In the scenarios studied in this work, the new scale is set by Φ. The basic estimate exp(−πm2/Φ) ∼ 1/√Nmodes suggests observational sensitivity to these massive particles, which we confirm in a detailed analysis.« less

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