Infinite-momentum frame description of relativistic heavy ion processes

Abstract

Relativistic heavy ion processes are discussed in a covariant model based on an infinite-momentum frame description. The model is an adaptation of the constituent interchange model (CIM) used in igh-energy hadronic processes. Various aspects of the model aare considered, especially those aspects concerning the connection between exclusive and inclusive processes and the implications on relativistic nuclear dynamics. We present theoretical predictions for single-particle inclusive spectra of pions and protons for proton-nucleus and nucleus-nucleus processes. The model is tested in various regions of spectra: fragmentation as well as central regions and small as well as finite transverse momentum regions. It is also tested with respect to its predictions for scaling and production of ultra-fast secondaries with energies beyond the kinematical limit. Comparison with data is on the whole quite satisfactory and provides convincing evidence for descriptions based on the infinite-momentum frame and the CIM. Discrepancies do show up (more significantly in transition regions from central to fragmentation spectra and also in large transverse momentum spectra). The question whether they originate from coherent scattering and/ or multichain cascading effects is left open.