The UA4 collaboration consisted of physicists from Amsterdam, Genova, Napoli, Pisa, Roma, California and CERN.

[3] The purpose of UA4/2 was to measure the ratio of real to the imaginary part of the forward elastic scattering amplitude.

[2] One had previously measured proton-antiproton cross-sections at the Intersecting Storage Rings, but as the Proton-Antiproton Collider — a modification of the Super Proton Synchrotron — began operating, the measurements could be done in a new energy range: up to 540 GeV center-of-mass energy.

Elastic events were detected by high resolution wire chambers and scintillation-counter hodoscopes.

[4] After the period of data taking, the UA4 collaboration could conclude that proton-antiproton cross-section indeed rises with energy.