Matching WMAP 3-yrs results with the Cosmological Slingshot Primordial Spectrum

Abstract

We consider a recently proposed scenario for the generation of primordial cosmological perturbations, the so called Cosmological Slingshot scenario. We firstly obtain a general expression for the Slingshot primordial power spectrum which extends previous results by including a blue pre-bounce residual contribution at large scales. Starting from this expression we numerically compute the CMB temperature and polarization power spectra arising from the Slingshot scenario and show that they excellently match the standard WMAP 3-years best-fit results. In particular, if the residual blue spectrum is far above the largest WMAP observed scale, the Slingshot primordial spectrum fits the data well by only fixing its amplitude and spectral index at the pivot scale k_p=10^{-3}h x Mpc^{-1}. We finally show that all possible distinctive Slingshot signatures in the CMB power spectra are confined to very low multipoles and thus very hard to detect due to large cosmic variance dominated error bars at these scales.Comment: 9 pages, 4 figures; v3 clarifications added, version accepted for publication in Gen. Rel. Grav. 200