  The probability of a projectile nucleon to traverse a target nucleus without
interaction is calculated for central Si-Pb collisions and compared to the data
of E814. The calculations are performed in two independent ways, via Glauber
theory and using the transport code UrQMD. For central collisions Glauber
predictions are about 30 to 50% higher than experiment, while the output of
UrQMD does not show the experimental peak of beam rapidity particles.
