Coherent Production on Nuclei Does Not Measure Total Cross Sections for Unstable Particles

Abstract

We calculate diffractive production in nucleon-nucleus collisions using a parton model. We fit the result by the standard optical-model formula, and obtain estimates of 12-30 mb for the cross section of the diffractively produced system on a nucleon. The actual value of that cross section in the model is 65 mb. Estimates for the total cross section of an unstable hadron which are based on the $A$ dependence of coherent production should therefore not be trusted.