abstract

The observability of physical quantities in general relativity is discussed by means of “operational observations”. Application is made to planetary motion.

abstract

Physics of baryonium is discussed within dual \(S\)-matrix framework. Some difficulties within the context of Standard FESR are pointed out. The experimental situation concerning the baryonium spectroscopy and phenomenology of baryonium exchange in two body and inclusive reactions is reviewed. Phenomenological evidence for \(\omega \)-baryonium mixing is presented. A model for this mixing based on dual unitarisation scheme is discussed.

abstract

The various theoretical descriptions of jets are discussed, including lowest order and leading logarithm calculations in QCD, as well as phenomenological models for non-perturbative fragmentation. Recent results concerning jet broadening, general branching equations and alternatives to the quark cascade model are emphasized.

abstract

It is well known that the charmonium model cannot offer any explanation for the surprisingly strong suppressions of the decays \(\psi (4.03) \to {\rm D}\bar {\rm D}\) and \(\psi (4.42) \to {\rm D}\bar {\rm D}\), \({\rm F}\bar {\rm F}\). In the literature various models have been suggested in order to account for the suppression of the \({\rm D}\bar {\rm D}\) mode \(\psi (4.03)\)-decay but these models are unable to explain the suppressions of the \({\rm D}\bar {\rm D}\) and \({\rm F}\bar {\rm F}\) modes in \(\psi (4.42)\)-decay. This note presents a model-tndependent explanation for the suppressions of the decays concerned.