An experimental study of large-angle elastic scattering of charged mesons and antiprotons on protons at 20 and 30 GeV/c incident momenta

A description is given of an experiment to study elastic scattering of πsup(+-), Ksup(+-) and anti p on protons at c.m. scattering angles from 450 to 1000 at incident laboratory momenta 20 GeV/c and 30 GeV/c. The corresponding t range is from -6.2 (GeV/c)2 to -28 (GeV/c)2. There are no previous observations for these reactions in this t range. High intensity and large geometrical acceptance were required in order to measure the low cross sections. The experiment used a double-arm spectrometer. MWPCs were used for reconstruction, and threshold and differential Cerenkov counters for identification. Scintillation counters, Cerenkov counters and a hadron calorimeter were used in the trigger. The trigger logic utilized specially designed matrices and a hard wired microprocessor. The π-p elastic scattering cross sections follow approximately the dimensional counting rule from 3.5 GeV/c and up to 30 GeV/c. The cross sections decrease by seven orders of magnitude in this energy range. The data is compared to quark models. None of these models give a comprehensive description of the results. However, some modifications to these models improve their consistency with the data. (orig.)