Small angle elastic scattering

The Fermilab results on charged hadron (π+, π-, K+, K-, p+, p-) elastic scattering are reported. Using three different experimental apparatus the differential cross sections were measured for the forward elastic scattering of the hadrons on protons at incident particle momenta of 50, 70, 100 and 200 GeV/c. Preliminary data are given on parameter rho, the ratio of the real to the imaginary parts of the forward scattering amplitude. The experimental data serve the conclusion that (1) the distributions for particles and antiparticles are very similar; (2) all data at 50 and 100 GeV/c are well described by the relation exp(bt+ct2); (3) the 200 GeV/c πp and pp data do not make a good fit to the exp(bt+ct2) form. A break appears in the data near t=-0.4(GeV/c)2; (4) for π-p and pp, there is a substantial increase of the slope in the region of small absolute values of t in the transition from 50 to 200 GeV/c. However, beyond absolute value of t=0.8(GeV/c)2 the π+p, π-p, K+p and K-p distributions become very similar and differ little from lower energy data. (Z.J.)