Regge theory of low pT hadronic interactions

This book deals with the consequences for hadronic physics of Regge's assumption that the S-matrix is an analytical function of the variable j, the extension to the complex plane of the usual angular momentum. The simple Regge-pole picture of the sixties has given way to the far more complicated supercritical Pomeron of the seventies. The main problem si the coexistence of s- and t-channel unitarity in a regime of increasing cross-sections. The Reggeon calculus provides a theoretical scheme with these properties which is also suitable for a phenomenological description of hadronic scattering on hadrons and on nuclei at high energy. The material is arranged in a sequence that roughly follows the historical development of the field. The first chapter deals with the main hypothesis of j-plane analyticity. The second chapter reviews the basic properties of multiparticle production in processes in which a singe Regge pole is exchanged. In the third chapter the unavoidable complication of Regge cuts is introduced perturbatively. The fourth chapter deals with multiple Pomeron exchanges and with the problems that these processes create for s-channel unitarity and for the self-consistency of the theory. In chapters five and six the theoretical development of the Reggeon calculus is described. Chapter seven studies the properties of multiparticle production in the critical and supercritical regimes. In chapter eight the subject of the space-time structure of the Reggeon calculus is reviewed in order to give an intuitive understanding of the main features of this scheme for the hadronic interactions with an extended target such as a nucleus. The onnections of the Reggeon calculus with a field theoretical approach based on quantum chromodynamics are examined in the final chapter and the main phenomenological tests of this type of approach are indicated. (author). refs.; figs.; tabs