CDM accelerating cosmology as an alternative to ΛCDM model

A new accelerating cosmology driven only by baryons plus cold dark matter (CDM) is proposed in the framework of general relativity. In this scenario the present accelerating stage of the Universe is powered by the negative pressure describing the gravitationally-induced particle production of cold dark matter particles. This kind of scenario has only one free parameter and the differential equation governing the evolution of the scale factor is exactly the same of the ΛCDM model. For a spatially flat Universe, as predicted by inflation (Ωdm+Ωbaryon = 1), it is found that the effectively observed matter density parameter is Ωmeff = 1−α, where α is the constant parameter specifying the CDM particle creation rate. The supernovae test based on the Union data (2008) requires α ∼ 0.71 so that Ωmeff ∼ 0.29 as independently derived from weak gravitational lensing, the large scale structure and other complementary observations