Predictions of single field inflation for the tensor/scalar ratio and the running spectral index
- Observatoire de Paris, LERMA, Laboratoire Associe au CNRS UMR 8112, 61, Avenue de l'Observatoire, 75014 Paris (France)
We study the single field slow-roll inflation models that better agree with the available CMB and LSS data including the three years WMAP data: new inflation and hybrid inflation. We study these models as effective field theories in the Ginsburg-Landau context: a trinomial potential turns out to be a simple and well motivated model. The spectral index n{sub s} of the adiabatic fluctuations, the ratio r of tensor to scalar fluctuations and the running index dn{sub s}/dlnk are studied in detail. We derive explicit formulas for n{sub s}, r and dn{sub s}/dlnk and provide relevant plots. In new inflation, and for the chosen central value n{sub s}=0.95, we predict 0.03<r<0.04 and -0.000 70<dn{sub s}/dlnk<-0.000 55. In hybrid inflation, and for n{sub s}=0.95, we predict r{approx_equal}0.2 and dn{sub s}/dlnk{approx_equal}-0.001. Interestingly enough, we find that in new inflation n{sub s} is bounded from above by n{sub smax}=0.961 528... and that r is a two valued function of n{sub s} in the interval 0.96<n{sub s}<n{sub smax}. In the first branch we find r<r{sub max}=0.114 769.... In hybrid inflation we find a critical value {mu}{sub 0crit}{sup 2} for the mass parameter {mu}{sub 0}{sup 2} of the field {sigma} coupled to the inflaton. For {mu}{sub 0}{sup 2}<{lambda}{sub 0}M{sub Pl}{sup 2}/192, where {lambda}{sub 0} is the cosmological constant, hybrid inflation yields a blue tilted n{sub s}>1 behavior. Hybrid inflation for {mu}{sub 0}{sup 2}>{lambda}{sub 0}M{sub Pl}{sup 2}/192 fulfills all the present CMB+LSS data for a large enough initial inflaton amplitude. Even if chaotic inflation predicts n{sub s} values compatible with the data, chaotic inflation is disfavored since it predicts a too high value r{approx_equal}0.27 for the ratio of tensor to scalar fluctuations. The model which best agrees with the current data and which best prepares the way to the expected data r(less-or-similar sign)0.1, is the trinomial potential with negative mass term: new inflation.
- OSTI ID:
- 20871193
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 74, Issue 6; Other Information: DOI: 10.1103/PhysRevD.74.063519; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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