Determination of the real part of the {\eta}'-Nb optical potential

TL;DR

This study measures the {ta}' meson interactions with niobium nuclei, revealing a shallow attractive potential that impacts the feasibility of detecting bound states.

Contribution

First measurement of the {ta}'-Nb optical potential using photoproduction data and model comparison, providing new insights into meson-nucleus interactions.

Findings

Attractive potential of -(41 (stat)  syst) MeV at nuclear matter density.

Potential depth consistent with previous measurements on lighter nuclei.

Shallow potential suggests difficulty in observing {ta}'-nucleus bound states.

Abstract

The excitation function and momentum distribution of {\eta}' mesons have been measured in photoproduction off 93^Nb in the energy range of 1.2-2.9 GeV. The experiment has been performed with the combined Crystal Barrel and MiniTAPS detector system, using tagged photon beams from the ELSA electron accelerator. Information on the sign and magnitude of the real part of the {\eta}'-Nb potential has been extracted from a comparison of the data with model calculations. An attractive potential of -(41 \pm 10(stat) \pm 15(syst)) MeV depth at normal nuclear matter density is deduced within model uncertainties. This value is consistent with the potential depth of -(37 \pm 10(stat) \pm 10(syst)) MeV obtained in an earlier measurement for a light nucleus (carbon). This relatively shallow {\eta}'-nucleus potential will make the search for {\eta}'-nucleus bound states more difficult.