Evolution and observational signature of diffused antiworld

The existence of macroscopic regions with antibaryon excess in the baryon a symmetric Universe with general baryon excess is the possible consequence o f practically all models of baryosynthesis, Diffusion of matter and antimat ter to the border of antimatter domains defines the minimal scale of the an timatter domains surviving to the present time. A model of diffused antiwor ld is considered, in which the density within the surviving antimatter doma ins is too low to form gravitationally bound objects. The possibility to te st this model by measurements of cosmic gamma ray fluxes is discussed. The expected gamma ray flux is found to be acceptable for modern cosmic gamma r ay detectors and for those planned for the near future. (C) 2000 Elsevier S cience B.V. All rights reserved.