Highenergy pp̄ and pp forward elastic scattering and total cross sections
Abstract
The present status of elastic pp and pp̄ scattering in the highenergy domain is reviewed, with emphasis on the forward and nearforward regions. The experimental techniques for measuring σ_{tot}, ρ, and B are discussed, emphasizing the importance of the region in which the nuclear and Coulomb scattering interfere. The impactparameter representation is exploited to give simple didactic demonstrations of important rigorous theorems based on analyticity, and to illuminate the significance of the slope parameter B and the curvature parameter C. Models of elastic scattering are discussed, and a criterion for the onset of "asymptopia" is given. A critique of dispersion relations is presented. Simple analytic functions are used to fit simultaneously the real and imaginary parts of forward scattering amplitudes for both pp and pp̄, obtained from experimental data for σ_{tot} and ρ. It is found that a good fit can be obtained using only five parameters (with a cross section rising as ln^{2}s), over the energy range 5<s<62 GeV. The possibilities that (a) the cross section rises only as lns, (b) the cross section rises only locally as ln^{2}s, and eventually goes to a constant value, and (c) the crosssection difference between pp and pp̄ does not vanish as s>∞ are examined critically. The nuclear slope parameters B are also fitted in a modelindependent fashion. Examination of the fits reveals a new regularity of the pp̄ and the pp systems. Predictions of all of the elastic scattering parameters are made at ultrahigh energies, and are compared to the available SPS collider measurements.
 Publication:

Reviews of Modern Physics
 Pub Date:
 April 1985
 DOI:
 10.1103/RevModPhys.57.563
 Bibcode:
 1985RvMP...57..563B