Sharp Decrease of the Effective Cosmological Constant in the Poincare Gauge Theory of Gravity with Minimal Self-Acting Scalar Field

The stage of a super-early (primordial) Universe is considered on the basis of Poincare gauge theory of gravity in the presence of a cosmological scalar field with an extremely weak self-action. For this purpose, field equations were obtained for a homogeneous and isotropic metric. A solution has been found at which the scale factor experiences an inflationary increase, and the effective cosmological constant has a sharp decrease from a huge value near the Big Bang to a small modern value. This fact solves the “cosmological constant problem.” It is predicted that the effective cosmological constant decreases extremely slowly throughout the lifetime of the Universe.