DARK-MATTER AND STRUCTURE FORMATION WITH LATE DECAYING PARTICLES

Since it became evident that the CDM model for cosmic structure format ion predicts smaller power on large scales than observed, many alterna tives have been suggested. Among them, the existence of late decaying particle can cure it by delaying the beginning of the matter dominatio n and increasing the horizon length at that time. We discuss the reali zation of this scenario and present the light neutrino and the light a xino as possible examples of a working particle physics model. We poin t out that the increased power at sub-galaxy scale predicted by this s cenario could lead to rich sub-galaxy structures.