Unitarity pion production and the multi-ladder pomeron

Abstract

In general this thesis is concerned with high energy elementary particle physics. In particular it discusses the solution of the unitarity equation when the input multiparticle production amplitude is given by a specific model. The main quantities which are calculated and predicted are; (i) the intercepts of Reggeon and exotic trajectories, (ii) the average multiplicities of the produced particles and charge transfer (Δ Q), (iii) and finally the relative probabilities of Charge exchange |ΔQ| = 2/(ΔQ=0+ |ΔQ| =2) and |ΔQ| = 3/(|ΔQ| =1+ |ΔQ| =3). Chapter one is a general introduction to the field. The physical motivations for using a peripheral description for 2→n amplitude and a multiperipheral description for the 2→n amplitude are discussed. The physical consequences of dual unitarization (or topological expansion) are discussed in Chapter two. Using quark-duality diagrams we have calculated many interesting physical quantities, e.g. the Residue and intercept of exotic exchange, the IOZ rule and its violation. In chapter three we introduce our pion production model for the A(_2)→n amplitude, where we do not impose exchange degeneracy between the 1=0 and I =1 trajectories, and we include (in addition to I=0, 1 trajectories) two exotic trajectories (X, Y) of opposite G-parity. The intercept of the output Reggeons and Exotic are calculated and a reasonable spectrum is obtained. In chapter four we repeat the calculations of chapter three when the I-Spin 0 partner of the pions, i.e. the ɱ is produced (in addition to π’s) Since, however, ɱ is heavier than the pions, we associate a suppression factor X when ɱ is produced. The main effect of the inclusion of ɱ is to push up (down) the positive (negative) G-parity states. This effect, however, is small compared to the original results, i.e. the results when only pions are produced. The average multiplicities of the produced particles and charge transfer (ΔQ) ere calculated in Chapter five in the context of both models of Chapters 3 and 4. These results are compatible with the moderate energy data but they are too small compared to high energy data. Finally, in Chapter six we introduce a multi-ladder model for the Pomeron, and we show how the data at high energy can be described by the model. In particular, we compare the relative probabilities of charge exchange predicted by the model with the new data of Lamia et a.l(^16)