Punctuated inflation and the low CMB multipoles

Abstract

We investigate inflationary scenarios driven by a class of potentials which are similar in form to those that arise in certain minimal supersymmetric extensions of the standard model. We find that these potentials allow a brief period of departure frominflation sandwiched between two stages of slow roll inflation. We show that such a background behavior leads to a step like featurein the scalar power spectrum.We set the scales such that the drop in the power spectrum occurs at a length scale that corresponds to the Hubble radius today — a feature that seems necessary to explain the lower power observed in the quadrupole moment of the Cosmic Microwave Background (CMB) anisotropies. We perform a Markov Chain Monte Carlo analysis to determine the values of the model parameters that provide the best fit to the recent WMAP 5-year data for the CMB angular power spectrum. We find that an inflationary spectrum with a suppression of power at large scales that we obtain leads to a much better fit (with justone extra parameter, χeff2 improves by 6.62) of the observed data when compared to the best fit reference ΛCDM model with a featureless, power law, primordial spectrum.