High Energy Scattering of Hadrons

Abstract

In these lectures we shall discuss some recent developments in the theory of elastic scattering of hadrons (strongly interacting particles) at high energy and small momentum transfers. By “high energy” we mean here the region GeV/c, where pL is the laboratory momentum of the incident particle; the highest value of pL available with present accelerators is about 30 Gev/c for protons. This region is characterized by the fact that cross sections are found to be smooth, slowly varying, in certain cases even nearly constant, functions of pL without any structure. By “small momentum transfers” we mean the region of the forward diffraction peak. At present, experimental high energy data are available for PP, PN, P, N, π±P, K±P and K±N reactions, where P = proton, N = neutron. We shall deal with two recently proposed models which have been rather successful in predicting relations between the various meson-baryon and baryon-baryon cross sections at high energies, namely the quark model [1] – [8] (Ch. II), and the combination of Regge pole model and current algebra [9], [10] (Ch. III). In Ch. I, we briefly mention a few general asymptotic properties of elastic scattering amplitudes, which are useful for the discussion in the last two Chapters.