Energy dependence of the nucleon-nucleon σ tot

The nucleon-nucleon total cross section σ tot is an important experimental quantity in the understanding of hadronic interactions. The behavior of the energy dependence of σ tot has changed as the energy has increased. In the 1960's data were consistent with the belief that all cross sections would eventually approach constant values as s → ∞. By the 1970's, as s increased, all cross sections fell, reached a minimum and then rose. Results available in the early and mid 1980's showed that σ tot continued increasing. The most recent data from the Fermilab Tevatron Collider show that σ tot continue to show a rise as the energy increases, consistent with log 2 s. These new results provide an ideal opportunity to present a review of the behavior of σ tot. In this work, the experimental status of the nucleon-nucleon σ tot, with data from the 1960's to the most recent data from the Fermilab Tevatron Collider, is reviewed. I will also outline the open questions for the next higher colliders, LHC (√ s = 17 TeV) and SSC (√ s = 40 TeV). The work emphasizes the importance of new measurements coming from these higher energy colliders. (Author)