Hadronic matter current distribution inside a polarized nucleus and a polarized hadron

Abstract

The concept of nucleonic current density (or velocity profile) inside a polarized nucleus and the concept of hadronic matter current density inside a polarized hadron are introduced. Utilizing the increasing opaqueness of hadrons relative to each other at increasing relative velocities, these current densities can be obtained from a measurement of the R( t) parameter in elastic hadron-nucleus and elastic hadron-hadron scattering. For very high energies, the spin dependence in elastic hadron-hadron scattering will be solely due to this non-vanishing R( t) parameter. Measurements of R( t) and therefore the nucleonic current or hadronic matter current thus provide powerful probes for the structure of polarized nuclei and hadrons. The results can be used to check nuclear theory and models of hadron structure. Estimates of the magnitude of R are given by assuming the proportionality between the hadronic matter density-current distribution and the electric charge-current distribution. This proportionality hypothesis which is heuristic is shown to be dependent on the concept of homogenization and the principle of minimum electromagnetic interactions for the basic constituents of hadrons. In the appendix it is shown that the spin of a Dirac particle does involve motion (currents).