Relation between Scattering and Absorption in the Pais-Piccioni Phenomenon

Abstract

The expressions for the ${\ensuremath{\theta}}_{1}$ and ${\ensuremath{\theta}}_{2}$ amplitudes in a beam of neutral $\ensuremath{\theta}$ mesons traversing an absorber are put in terms of forward-scattering amplitudes. It is discovered that a phase-shift term as well as an absorption term is needed to describe the regeneration of ${\ensuremath{\theta}}_{1}$ mesons in the unscattered beam.A simple relation is derived between the intensities of the above process and of the ${\ensuremath{\theta}}_{1}$ mesons regenerated by scattering. Experimental verification of the relation may give additional information about the nature of the neutral $K$ mesons.