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. CroninMoscow, February 25

Two techniques:

• detect shower particles on the ground

• detect air fluorescence produced by shower particles

M Hillas

1984

3

proton + cmb -> + nucleon

Assume E-2.5 spectrum

Beyond 1500 gm/cm2

electromagnetic particlesabsorbed. (Highly inclined showers)

90 % of particleswithin Moliereradius of ≤ 100 m

Note: total energycarried by muons ≤ 10%

Energy deposit in1.2 meters of water

At 1000 meters from core

Go to black board

Two techniques:

• detect shower particles on the ground

• detect air fluorescence produced by shower particles

A “perfect” hybrid event: few are as beautiful as this one !

Miguel MostafaNew Mexico/Utah

To be continued