Speaker
Description
We investigate the Feynman-$x$ spectra of the neutrons produced in the very forward direction in $ep$ collisions using the impact-parameter dependent color dipole model with and without saturation. Our analysis demonstrates that the W and $Q^2$ dependence of the cross-section are independent of the presence of a forward neutron, as predicted by Feynman-scaling. The models prediction are compared with the available HERA data for leading neutrons in $6<Q^2<100~GeV^2$, $70<W<245~GeV$ and our analysis show that Feynman scaling exists in both the models independent of the value of $Q^2$. Thus, we infer that the HERA measurements of semi-inclusive leading neutron production data are insensitive to the non-linear physics and these spectra may not be able to distinguish the gluon saturation effects in future $ep$ colliders. Additionally, we provide an estimate of the pion structure function at small $x$ and further show that the observables in exclusive measurements of the leading neutrons with a vector meson in the final state are sensitive to saturation physics at small $x$.
| Submitted on behalf of a Collaboration? | No |
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