Pionic Atom Spectroscopy in the (d,3He) reaction at finite angles

TL;DR

This paper theoretically investigates the formation of deeply bound pionic atoms via (d,3He) reactions at finite angles, predicting energy spectra and their dependence on scattering angles to aid experimental studies of pion properties and chiral symmetry restoration.

Contribution

It provides a theoretical analysis of pionic atom formation at finite angles, highlighting how different states dominate spectra and proposing a method to systematically study pion-nucleus interactions.

Findings

Different pion-bound and neutron-hole states dominate spectra at various angles.

Finite angle measurements can systematically reveal pionic bound states.

The study supports experimental exploration of pion properties and chiral symmetry in nuclei.

Abstract

We study the formation of deeply bound pionic atoms in the (d,3He) reactions theoretically and show the energy spectra of the emitted 3He at finite angles, which are expected to be observed experimentally. We find that the different combinations of the pion-bound and neutron-hole states dominate the spectra at different scattering angles because of the matching condition of the reaction. We conclude that the observation of the (d,3He) reaction at finite angles will provide the systematic information of the pionic bound states in each nucleus and will help to develop the study of the pion properties and the partial restoration of chiral symmetry in nuclei.