Effects and detectability of quasi-single field inflation in the large-scale structure and cosmic microwave background

Quasi-single field inflation predicts a peculiar momentum dependence in the squeezed limit of the primordial bispectrum which smoothly interpolates between the local and equilateral models. This dependence is directly related to the mass of the isocurvatons in the theory which is determined by the s...

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Bibliographic Details
Published in:Journal of cosmology and astroparticle physics 2012-08, Vol.2012 (8), p.i-36
Main Authors: Sefusatti, Emiliano, Fergusson, James R, Chen, Xingang, Shellard, E PS
Format: Article
Language:English
Subjects:
AMPLITUDES
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
CORRECTIONS
Cosmic microwave background
COSMOLOGICAL MODELS
COSMOLOGY
ENERGY SPECTRA
GALAXIES
Inflation
Initial conditions
MASS
Mathematical models
Non-Gaussian
RELICT RADIATION
SUPERSYMMETRY
Uncertainty
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Summary:Quasi-single field inflation predicts a peculiar momentum dependence in the squeezed limit of the primordial bispectrum which smoothly interpolates between the local and equilateral models. This dependence is directly related to the mass of the isocurvatons in the theory which is determined by the supersymmetry. Therefore, in the event of detection of a non-zero primordial bispectrum, additional constraints on the parameter controlling the momentum-dependence in the squeezed limit becomes an important question. We explore the effects of these non-Gaussian initial conditions on large-scale structure and the cosmic microwave background, with particular attention to the galaxy power spectrum at large scales and scale-dependence corrections to galaxy bias. We determine the simultaneous constraints on the two parameters describing the QSF bispectrum that we can expect from upcoming large-scale structure and cosmic microwave background observations. We find that for relatively large values of the non-Gaussian amplitude parameters, but still well within current uncertainties, galaxy power spectrum measurements will be able to distinguish the QSF scenario from the predictions of the local model. A CMB likelihood analysis, as well as Fisher matrix analysis, shows that there is also a range of parameter values for which Planck data may be able distinguish between QSF models and the related local and equilateral shapes. Given the different observational weightings of the CMB and LSS results, degeneracies can be significantly reduced in a joint analysis.
ISSN:1475-7516
1475-7516
DOI:10.1088/1475-7516/2012/08/033