Fusion of strings as a hadronic accelerator
  It is shown that the fusion of strings is a source of particle production in nucleus--nucleus collisions outside the kinematical limits of nucleon--nucleon collisions. The spectrum of different particles is compared with the high energy data on p--A collisions obtaining a reasonable agreement. Results for A--B collisions at $\sqrt{s}=19.4$ AGeV and $\sqrt{s}=200$ AGeV are given. It is shown that the fusion of strings can accelerate particles up to the highest energy detected in cosmic rays without help of any additional cosmic accelerator. Also the rise of the average shower depth of maximun for cosmic rays in the energy range between $10^{16}$ eV and $10^{19}$ eV can be explained by the same mechanism without requiring any change in the chemical composition. 
N. Armesto, M. A. Braun, E. G. Ferreiro, C. Pajares and Yu. M.   Shabelski