Quest for the origin of dark matter, dark energy, and dark radiation

Rrecent data of cosmic microwave background (CMB) anisotropy have indicated the significance of cold dark matter and dark energy to model the accelerating universal expansion in flat cosmology. Motivated by this observation, we propose a disappearing cold dark matter model in brane world cosmology with extra-dimension, and also study a quintessential inflation in order to identify the time varying dark energy as the cosmological constant at the present epoch. Massive cold dark matter particle is likely to disappear when it is quantized in a Randall-Sundrum noncompact higher dimensional AdS(5) space-time. We look for cosmological evidence for this new paradigm and show that this new model is consistent with all data at the 95 % C.L., satisfying presently available all sorts of observational constraints from the redshift-luminosity realation of Type Ia supernovae (SNe), the mass-to-light ratios of galaxy clusters, and the power spectrum of cosmic microwave background. Quintessence scalar field couples with the dominant constituent and shows time variation along the evolutionary history of the universe. It only acts like a cosmological constant after the onset of the matter dominated epoch. These models can affect, and therefore be constrained by, primordial nucleosynthesis and the CMB at the epoch of photon decoupling. We analyze one popular form for the quintessence field with and without a supergravity correction and quantify constraints on the allowed initial conditions and parameters for the effective potential.