Target Fragmentation of the Nucleon at High Energies

Abstract

We calculate target fragmentation in $p p \to n X$ and $\gamma p \to n X$ reactions in the meson cloud picture of the nucleon. The $p p \to n X$ reaction is used to fix the $pn\pi^+$ form factor for two different models. We take into account the possible destruction of the residual neutron by the projectile. Using the form factor from the hadronic reaction we calculate photoproduction and small $x_{Bj}$ electroproduction of forward neutrons at HERA. In photoproduction we observe about the same amount of absorption as in the hadronic reaction. For deep inelastic events screening is found to be negligible. The signature of this color transparency on the nucleon is a shift of the $dN/dE_n$ distribution to higher neutron energies for photofragmentation