Determination of the eta'-proton scattering length in free space

TL;DR

This paper measures the eta'-proton scattering length in free space by analyzing near-threshold proton-proton collisions with high-resolution detectors, providing key parameters for understanding eta'-nucleon interactions.

Contribution

It introduces a precise method combining high-resolution data to determine the eta'-proton scattering length, a novel measurement in free space.

Findings

Re(a_{p eta'}) = 0+-0.43 fm

Im(a_{p eta'}) = 0.37(+0.40)(-0.16) fm

Enhanced understanding of eta'-nucleon interactions

Abstract

Taking advantage of both the high mass resolution of the COSY-11 detector and the high energy resolution of the low-emittance proton-beam of the Cooler Synchrotron COSY we determine the excitation function for the pp --> pp eta' reaction close-to-threshold. Combining these data with previous results we extract the scattering length for the eta'-proton potential in free space to be Re(a_{p eta'}) = 0+-0.43 fm and Im(a_{p eta'}) = 0.37(+0.40)(-0.16) fm.