Constraining running non-gaussianity
- Institut de Physique Théorique, CEA, IPhT, F-91191 Gif-sur-Yvette (France)
- DAMTP, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
- Center for Astrophysics, Harvard University, Cambridge, MA 02138 (United States)
- Center for Particle Astrophysics, Fermilab, Batavia, IL 60510 (United States)
- Laboratory for Elementary Particle Physics, Cornell University, Ithaca, NY 14853 (United States)
The primordial non-Gaussian parameter f{sub NL} has been shown to be scale-dependent in several models of inflation with a variable speed of sound, such as Dirac-Born-Infeld (DBI) models. We perform a Fisher matrix analysis of the bispectra of the temperature and polarization of the Cosmic Microwave Background (CMB) radiation and derive the expected constraints on the parameter n{sub NG} that quantifies the running of f{sub NL}(k) for current and future CMB missions. We find that CMB information alone, in the event of a significant detection of the non-Gaussian component, corresponding to f{sub NL} = 50 for the local model and f{sub NL} = 100 for the equilateral model of non-Gaussianity, is able to determine n{sub NG} with a 1-σ uncertainty of n{sub NG} ≅ 0.1 and Δn{sub NG} ≅ 0.3, respectively, for the Planck mission and a factor of two better for CMBPol. In addition, we show how future large-scale structure observations should achieve results comparable to or even better than those from the CMB, while showing some complementarity due to the different distribution of the non-Gaussian signal over the relevant range of scales. Finally, we compare our findings to the predictions on the amplitude and running of non-Gaussianity of DBI inflation, showing how the constraints on a scale-dependent f{sub NL}(k) translate into constraints on the parameter space of the theory.
- OSTI ID:
- 22273131
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 12 Vol. 2009; ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
Planck 2018 results
Primordial non-Gaussianity from the DBI Galileons