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Title: Inflation by alignment

Abstract

Pseudo-Goldstone bosons (pGBs) can provide technically natural inflatons, as has been comparatively well-explored in the simplest axion examples. Although inflationary success requires trans-Planckian decay constants, f≳M{sub p}, several mechanisms have been proposed to obtain this, relying on (mis-)alignments between potential and kinetic energies in multiple-field models. We extend these mechanisms to a broader class of inflationary models, including in particular the exponential potentials that arise for pGB potentials based on noncompact groups (and so which might apply to moduli in an extra-dimensional setting). The resulting potentials provide natural large-field inflationary models and can predict a larger primordial tensor signal than is true for simpler single-field versions of these models. In so doing we provide a unified treatment of several alignment mechanisms, showing how each emerges as a limit of the more general setup.

Authors:
 [1];  [2];  [2];  [3]
  1. PH -TH Division, CERN,CH-1211, Genève 23 (Switzerland)
  2. (Canada)
  3. Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22458350
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 06; Other Information: PUBLISHER-ID: JCAP06(2015)012; OAI: oai:repo.scoap3.org:10613; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ALIGNMENT; COSMOLOGICAL INFLATION; GOLDSTONE BOSONS; INFLATONS; KINETIC ENERGY; SIGNALS; STRING MODELS; STRING THEORY

Citation Formats

Burgess, C.P., Department of Physics & Astronomy, McMaster University,1280 Main Street West, Hamilton ON, Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo ON, and Roest, Diederik. Inflation by alignment. United States: N. p., 2015. Web. doi:10.1088/1475-7516/2015/06/012.
Burgess, C.P., Department of Physics & Astronomy, McMaster University,1280 Main Street West, Hamilton ON, Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo ON, & Roest, Diederik. Inflation by alignment. United States. doi:10.1088/1475-7516/2015/06/012.
Burgess, C.P., Department of Physics & Astronomy, McMaster University,1280 Main Street West, Hamilton ON, Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo ON, and Roest, Diederik. 2015. "Inflation by alignment". United States. doi:10.1088/1475-7516/2015/06/012.
@article{osti_22458350,
title = {Inflation by alignment},
author = {Burgess, C.P. and Department of Physics & Astronomy, McMaster University,1280 Main Street West, Hamilton ON and Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo ON and Roest, Diederik},
abstractNote = {Pseudo-Goldstone bosons (pGBs) can provide technically natural inflatons, as has been comparatively well-explored in the simplest axion examples. Although inflationary success requires trans-Planckian decay constants, f≳M{sub p}, several mechanisms have been proposed to obtain this, relying on (mis-)alignments between potential and kinetic energies in multiple-field models. We extend these mechanisms to a broader class of inflationary models, including in particular the exponential potentials that arise for pGB potentials based on noncompact groups (and so which might apply to moduli in an extra-dimensional setting). The resulting potentials provide natural large-field inflationary models and can predict a larger primordial tensor signal than is true for simpler single-field versions of these models. In so doing we provide a unified treatment of several alignment mechanisms, showing how each emerges as a limit of the more general setup.},
doi = {10.1088/1475-7516/2015/06/012},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 06,
volume = 2015,
place = {United States},
year = 2015,
month = 6
}
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  • The cosmic microwave background power spectra are studied for different families of single field new and chaotic inflation models in the effective field theory approach to inflation. We implement a systematic expansion in 1/N(e), where N(e)~;;50 is the number of e-folds before the end of inflation. We study the dependence of the observables (n(s), r and dn(s)/dlnk) on the degree of the potential (2n) and confront them to the WMAP3 and large scale structure data: This shows in general that fourth degree potentials (n=2) provide the best fit to the data; the window of consistency with the WMAP3 and LSSmore » data narrows for growing n. New inflation yields a good fit to the r and n(s) data in a wide range of field and parameter space. Small field inflation yields r<0.16 while large field inflation yields r>0.16 (for N(e)=50). All members of the new inflation family predict a small but negative running -4(n+1) x 10-4<=dn(s)/dlnk<=-2 x 10-4. (The values of r, n(s), dn(s)/dlnk for arbitrary N(e) follow by a simple rescaling from the N(e)=50 values.) A reconstruction program is carried out suggesting quite generally that for n(s) consistent with the WMAP3 and LSS data and r<0.1 the symmetry breaking scale for new inflation is |phi0|~;;10MPl while the field scale at Hubble crossing is lbar phi(c) rbar~;;M(Pl). The family of chaotic models features r>=0.16 (for N(e)=50) and only a restricted subset of chaotic models are consistent with the combined WMAP3 bounds on r, n(s), dn(s)/dlnk with a narrow window in field amplitude around |phi(c)|~;;15M(Pl). We conclude that a measurement of r<0.16 (for N(e)=50) distinctly rules out a large class of chaotic scenarios and favors small field new inflationary models. As a general consequence, new inflation emerges more favored than chaotic inflation.« less