Precision Spectroscopy of Antiprotonic Atoms for Investigation of Low-energy Antinucleon-nucleus Interactions

TL;DR

This paper proposes a high-precision x-ray spectroscopy experiment on antiprotonic calcium isotopes to improve understanding of low-energy antinucleon-nucleus interactions and refine existing theoretical models.

Contribution

It introduces a novel experimental approach using superconducting microcalorimeter detectors to measure isotope-dependent shifts and widths with high precision, addressing uncertainties in current models.

Findings

Enhanced constraints on the isovector parameter of the optical potential.

Refined data on antiprotonic atom energy shifts and widths.

Potential improvements in models for neutron-antineutron oscillation searches.

Abstract

We propose a high-precision x-ray spectroscopy experiment of antiprotonic atoms to advance the understanding of low-energy antinucleon-nucleus interactions. The current leading model of antiproton-nucleus interactions is based on an optical potential with parameters derived from a global fit to antiprotonic atom x-ray data across the periodic table. However, the isovector parameter of this potential remains poorly constrained due to uncertainties in nucleon distributions of the nuclei. To address this, we propose to use calcium isotopes with well-studied nucleon distributions to minimize these uncertainties. A superconducting microcalorimeter detector will provide a resolution of 50-70 eV in the energy range of interest, allowing high precision determination of the isotope-dependent strong-interaction shifts and widths. The outcomes of the proposed experiment can be used to refine the model of antinucleon-nucleus interactions and provide critical data for future experiments searching for neutron-antineutron oscillations.