A solution of the Randall-Sundrum model and the mass hierarchy problem

A solution of the Randall-Sundrum model for a simplified case (one wall) is obtained. It is given by the 1/ k 2 -expansion (thin-wall expansion), where 1/ k is the thickness of the domain wall. The vacuum setting is done by the five-dimensional (5D) Higgs potential and the solution is for a family of the Higgs parameters. The mass hierarchy problem is examined. Some physical quantities in four-dimensional (4D) world such as the Planck mass, the cosmological constant and fermion masses are focused. Similarity to the domain wall regularization used in the chiral fermion problem is explained. We examine the possibility that the 4D massless chiral fermion bound to the domain wall in the 5D world can be regarded as real 4D fermions such as neutrinos, quarks and other leptons.