Probing primordial symmetry breaking with the cosmic microwave background anisotropy

Abstract

There have been vigorous research attempts to test various modified gravity theories by using physics of the cosmic microwave background (CMB) anisotropy. In this article, with the CMB we try to distinguish two different scenarios of spontaneous symmetry breaking (SSB) in primordial era of the universe. The first scenario is a broken symmetric theory of gravity, which was suggested by A. Zee in 1979. The second scenario is an application of Palatini formalism to Zee's model and it combines the idea of SSB with Weyl scalar-tensor geometry.Since our new model based on Palatini formalism has geometrical feature, the scalar field coupled with gravity affects an evolution of Hubble parameter whereas Zee's model gives additional contributions to the energy-momentum tensor. Furthermore, it turns out that our model has different (from Zee's) sensitivity of CMB anisotropy power spectra with the scalar field mass. This fact enables us to verify distinct kinds of primordial symmetry breaking.