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Title: Resonant signatures of heavy scalar fields in the cosmic microwave background

Abstract

We investigate the possibility that a heavy scalar field, whose mass exceeds the Hubble scale during inflation, could leave non-negligible signatures in the Cosmic Microwave Background (CMB) temperature anisotropy power spectrum through the parametric resonance between its background oscillations and the inflaton fluctuations. By assuming the heavy scalar field couples with the inflaton derivatively, we show that the resonance can be efficient without spoiling the slow-roll inflation. The primordial power spectrum modulated by the resonance has a sharp peak at a specific scale and could be an origin of the anomalies observed in the angular power spectrum of the CMB. In some values of parameters, the modulated spectrum can fit the observed data better than the simple power-law power spectrum, though the resultant improvement of the fit is not large enough and hence other observations such as non-Gaussianity are necessary to confirm that the CMB anomalies are originated from the resonant effect of the heavy scalar field. The resonant signatures can provide an opportunity to observe heavy degrees of freedom during inflation and improve our understanding of physics behind inflation.

Authors:
;  [1];  [2];  [3]
  1. Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa Oiwake-Cho, Sakyo-Ku, Kyoto 606-8502 Japan (Japan)
  2. Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  3. Research Center for the Early Universe, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
Publication Date:
OSTI Identifier:
22279821
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2012; Journal Issue: 11; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; COSMOLOGY; DEGREES OF FREEDOM; ENERGY SPECTRA; FLUCTUATIONS; INFLATIONARY UNIVERSE; INFLATONS; MASS; OSCILLATIONS; RELICT RADIATION; RESONANCE; SCALAR FIELDS

Citation Formats

Saito, Ryo, Takamizu, Yu-ichi, Nakashima, Masahiro, and Yokoyama, Jun'ichi, E-mail: rsaito@yukawa.kyoto-u.ac.jp, E-mail: nakashima@resceu.s.u-tokyo.ac.jp, E-mail: takamizu@yukawa.kyoto-u.ac.jp, E-mail: yokoyama@resceu.s.u-tokyo.ac.jp. Resonant signatures of heavy scalar fields in the cosmic microwave background. United States: N. p., 2012. Web. doi:10.1088/1475-7516/2012/11/036.
Saito, Ryo, Takamizu, Yu-ichi, Nakashima, Masahiro, & Yokoyama, Jun'ichi, E-mail: rsaito@yukawa.kyoto-u.ac.jp, E-mail: nakashima@resceu.s.u-tokyo.ac.jp, E-mail: takamizu@yukawa.kyoto-u.ac.jp, E-mail: yokoyama@resceu.s.u-tokyo.ac.jp. Resonant signatures of heavy scalar fields in the cosmic microwave background. United States. doi:10.1088/1475-7516/2012/11/036.
Saito, Ryo, Takamizu, Yu-ichi, Nakashima, Masahiro, and Yokoyama, Jun'ichi, E-mail: rsaito@yukawa.kyoto-u.ac.jp, E-mail: nakashima@resceu.s.u-tokyo.ac.jp, E-mail: takamizu@yukawa.kyoto-u.ac.jp, E-mail: yokoyama@resceu.s.u-tokyo.ac.jp. Thu . "Resonant signatures of heavy scalar fields in the cosmic microwave background". United States. doi:10.1088/1475-7516/2012/11/036.
@article{osti_22279821,
title = {Resonant signatures of heavy scalar fields in the cosmic microwave background},
author = {Saito, Ryo and Takamizu, Yu-ichi and Nakashima, Masahiro and Yokoyama, Jun'ichi, E-mail: rsaito@yukawa.kyoto-u.ac.jp, E-mail: nakashima@resceu.s.u-tokyo.ac.jp, E-mail: takamizu@yukawa.kyoto-u.ac.jp, E-mail: yokoyama@resceu.s.u-tokyo.ac.jp},
abstractNote = {We investigate the possibility that a heavy scalar field, whose mass exceeds the Hubble scale during inflation, could leave non-negligible signatures in the Cosmic Microwave Background (CMB) temperature anisotropy power spectrum through the parametric resonance between its background oscillations and the inflaton fluctuations. By assuming the heavy scalar field couples with the inflaton derivatively, we show that the resonance can be efficient without spoiling the slow-roll inflation. The primordial power spectrum modulated by the resonance has a sharp peak at a specific scale and could be an origin of the anomalies observed in the angular power spectrum of the CMB. In some values of parameters, the modulated spectrum can fit the observed data better than the simple power-law power spectrum, though the resultant improvement of the fit is not large enough and hence other observations such as non-Gaussianity are necessary to confirm that the CMB anomalies are originated from the resonant effect of the heavy scalar field. The resonant signatures can provide an opportunity to observe heavy degrees of freedom during inflation and improve our understanding of physics behind inflation.},
doi = {10.1088/1475-7516/2012/11/036},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 11,
volume = 2012,
place = {United States},
year = {2012},
month = {11}
}