Physics (Internal)

From the CMB to fundamental physics - A closer look at n_s and r

This event is part of the HET Seminar Series.

Abstract: The cosmic microwave background contains a wealth of information about cosmology as well as high energy physics. It tells us about the composition and geometry of the universe, the properties of neutrinos, dark matter, and even about the conditions in our universe long before the cosmic microwave background was emitted. After a brief review of what we may hope to learn from it about inflation, I will review measurements of the angular power spectrum of temperature perturbations from Planck data by the Planck collaboration and by Renee Hlozek, David Spergel and myself. I will then combine these measurements with the recent measurement of the polarization of the cosmic microwave background by BICEP2 as well as the measurements of polarized emission from dust by the Planck collaboration to derive the current constraints on the spectral index of scalar perturbations and the amount of primordial gravitational waves. I will show that the data now disfavors the simplest model of inflation at 2-3 sigma depending on the choice of likelihood for the temperature data.