1. The Highest Energy Cosmic Rays I Propagation and Detection XXXIV ITEP Winter School of Physics Nucl Phys B (Proc Suppl) 138 (2005) 465-491 James W. Cronin Moscow, February 25

2. Two techniques: detect shower particles on the ground detect air fluorescence produced by shower particles

3. M Hillas 1984

5. 3 proton +  cmb ->  + nucleon

7. Assume E -2.5 spectrum

12. Beyond 1500 gm/cm 2 electromagnetic particles absorbed. (Highly inclined showers)

15. 90 % of particles within Moliere radius of ≤ 100 m

18. Note: total energy carried by muons ≤ 10%

19. Energy deposit in 1.2 meters of water

20. At 1000 meters from core

25. Go to black board

30. Two techniques: detect shower particles on the ground detect air fluorescence produced by shower particles

31. A “perfect” hybrid event: few are as beautiful as this one ! Miguel Mostafa New Mexico/Utah

32. To be continued