Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; Peking Univ, Dept Phys, Beijing 100871, Peoples R China
We discuss the vacuum energy density and the cosmological constant of dS(5) braneworld with a dilaton field. It is shown that a stable AdS(4) brane can be constructed and gravity localization can be realized. An explicit relation between the dS bulk cosmological constant and the brane cosmological constant is obtained. The discrete mass spectrum of the massive scalar field in the AdS(4) brane is used to acquire the relationship between the brane cosmological constant and the vacuum energy density. The vacuum energy density in the brane gotten by this method is in agreement with astronomical observations.