Why more hadronlike photons produce less particles on nuclear targets

Abstract

In hadron-nucleus interactions, the stronger is nuclear shadowing in the total cross section the higher is the multiplicity of secondary hadrons. In deep inelastic scattering, nuclear shadowing at small $x$ is associated with the hadronlike behaviour of photons as contrasted to the pointlike behaviour in the non-shadowing region of large $x$. In this paper we predict smaller mean multiplicity of secondary hadrons, and weaker fragmentation of the target nucleus, in deep inelastic leptoptoproduction on nuclei in the shadowing region of small $x$ as compared to the non-shadowing region of large $x$. This paradoxial conclusion has its origin in nuclear enhancement of the coherent diffraction dissociation of photons. We present numerical predictions for multiproduction in $\mu Xe$ interactions studied by the Fermilab E665 collaboration.