Primordial bound systems of superheavy particles as the source of ultra-high energy cosmic rays

Annihilation of superheavy particles in primordial bound systems is considered as the source of ultra-high energy cosmic rays (UHECR). Charge conservation makes them to be produced in pairs, and the estimated separation of particle and antiparticle in such pair is shown to be in some cases much smaller than the average separation determined by the averaged number density of considered particles. If the new U(1) charge is the source of a long range field similar to electromagnetic field, the particle and antiparticle, possessing that charge, can form primordial bound system with annihilation timescale, which can satisfy the conditions, assumed for this type of UHECR sources. These conditions severely constrain the possible properties of considered particles. So, the proposed mechanism of UHECR origin is impossible to realize, if the U(1) charged particles share ordinary weak, strong or electromagnetic interactions. It makes the proposed mechanism of pairing and binding of superheavy U(1) charged particles an effective theoretical tool in the probes of the physics of very early Universe and of the hidden sector of particle theory, underlying it.