Please send me E-mail, dow@ubpheno.physics.buffalo.edu, no later than Friday, February 10, 2006, 2 pm, with your thoughts on:

1. The discovery of muons in cosmic rays was an important step towards the development of the Standard Model. The mean lifetime of muons is 2.2 microseconds. The muons are produced in the earth's atmosphere with an energy of about 20 GeV, i.e. they travel with nearly the speed of light. Why are we still able to detect a large fraction of these muons at sea level, i.e. after they have traveled a distance of 15-20 km ?