We study the effect of a violation of the strong equivalence principle (SEP) on the cosmic microwave background (CMB). Such a violation would modify the weight of baryons in the primordial gravitational potentials and hence their impact in the establishment of the photon-baryon plasma acoustic oscillations before recombination. This cosmological Nordtvedt effect alters the odd peaks height of the CMB temperature anisotropy power spectrum. A gravitational baryonic mass density of the Universe may already be inferred at the first peak scale from the analysis of Wilkinson microwave anisotropy probe (WMAP) data. Experimental constraints on a primordial SEP violation are derived from a comparison with the Universe's inertial baryonic mass density measured either in a full analysis of the CMB, or in the framework of the standard big bang nucleosynthesis (BBN).
|Number of pages
|Physical Review D - Particles, Fields, Gravitation and Cosmology
|Published - Nov 2004
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Mathematical Physics