Abstract:
It is pointed out that the observed extremely high energy cosmic rays (EHECR) above 1011 GeV and the observed baryon asymmetry of the Universe (BAU) may have a common origin in baryon number violating decays of supermassive X particles released from cosmic topological defects (TDs) such as cosmic strings and monopoles. The X particles produced by TDs in the recent epochs produce the EHECR, while the BAU is created by X particles released from TDs mainly in the very early Universe. In this scenario the EHECR is predicted to contain baryons as well as antibaryons with a small asymmetry between the two.