Structure of double pionic atoms

TL;DR

This paper theoretically investigates the structure of double pionic atoms, analyzing how strong and electromagnetic interactions influence their binding energies, providing insights into pion interactions and multi-bosonic systems.

Contribution

It presents a theoretical evaluation of the effects of $\

Findings

Energy shifts of about 10 keV due to $\\pi\\pi$ strong interaction.

Energy shifts of about 100 keV due to electromagnetic interaction.

Potential to extract information on isospin $I=2$ $\\pi\\pi$ interaction.

Abstract

We study theoretically the structure of double pionic atoms, in which two negatively charged pions ($\pi^-$) are bound in the atomic orbits. The double pionic atom is considered to be an interesting system from the point of view of the multi bosonic systems. In addition, it could be possible to deduce valuable information on the isospin $I = 2$ $\pi\pi$ interaction and the pion-nucleus strong interaction. In this paper, we take into account the $\pi\pi$ strong and electromagnetic interactions, and evaluate the effects on the binding energies by perturbation theory for the double pionic atoms in heavy nuclei. We investigate several combinations of two pionic states and find that the order of magnitude of the energy shifts due to the $\pi\pi$ interaction is around 10 keV for the strong interaction and around 100 keV for the electromagnetic interaction for the ground states.