π±p,K±p,pp, andp¯pelastic scattering from 50 to 175 GeV/c

Abstract

The differential cross sections for the elastic scattering of ..pi../sup +/, ..pi../sup -/, K/sup +/, K/sup -/, p, and p-bar on protons have been measured in the t interval -0.04 to -0.75 GeV/sup 2/ at five momenta: 50, 70, 100, 140, and 175 GeV/c. The t distributions have been parametrized by the quadratic exponential form dsigma/dt = A exp( B abs. value(t) + C abs. value(t)/sup 2/ and the energy dependence has been described in terms of a single-pole Regge model. The pp and K/sup +/p diffraction peaks are found to shrink with ..cap alpha..' approx. 0.20 and approx. 0.15 GeV/sup -2/, respectively. The p-barp diffraction peak is antishrinking while ..pi../sup +/- and K/sup -/p are relatively energy-independent. Total elastic cross sections are calculated by integrating the differential cross sections. The rapid decline in sigma/sub el/ observed at low energies has stopped and all six reactions approach relatively constant values of sigma/sub el/. The ratio of sigma/sub el//sigma/sub tot/ approaches a constant value for all six reactions by 100 GeV, consistent with the predictions of the geometric-scaling hypothesis. This ratio is approx. 0.18 for pp and p-barp, and approx. 0.12--0.14 for ..pi../sup +/- and K/sup +/-. A crossover is observedmore » between K/sup +/p and K/sup -/p scattering at abs. value t approx =0.19 GeV/sup 2/, and between pp and p-barp at abs. value t approx=0.11 GeV/sup 2/. Inversion of the cross sections into impact-parameter space shows that protons are quite transparent to mesons even in head-on collisions. The probability for a meson to pass through a proton head-on without interaction inelastically is approx. 20%, while it is only approx. 6% for an incident proton or antiproton. Finally, the results are compared with various quark-model predictions.« less