(d,3He) reaction on odd-neutron nuclear target for the formation of deeply bound pionic atoms

TL;DR

This study explores the (d,3He) reaction on odd-neutron nuclear targets to observe pionic states with minimal residual interaction effects, aiming to enhance the precision of pion binding energy measurements and understand strong interaction symmetries.

Contribution

The paper introduces a modified theoretical framework for pionic atom spectroscopy on odd-neutron targets, expanding the experimental and theoretical understanding of pionic states in nuclear physics.

Findings

Pionic states in odd-neutron targets are less affected by residual interactions.

Numerical results for 117Sn target demonstrate the feasibility of the approach.

The study proposes future experiments at RIBF/RIKEN to validate the theory.

Abstract

We consider the pionic atom spectroscopy by the (d,3He) reaction on an odd-neutron nuclear target in this article, which has not been investigated so far. In the (d,3He) reaction on the odd-neutron nuclear target, we can observe the pionic states in the even-neutron nucleus with spin-parity 0+. We expect that this pionic state does not have the additional shifts due to the effects of the residual interaction between neutron-hole and pionic states. For the even-neutron nuclear target cases, we may have to take into account the residual interaction effects to deduce the binding energies of the pionic states precisely from the high precision experimental data since the final pionic states are the pion-particle plus neutron-hole states. Thus, in addition to widening the domain of the pionic atom spectroscopy in nuclear chart, the present study of the (d,3He) reaction on the odd-neutron target is considered to be important to deduce extremely precise information on the binding energies of the observed pionic states, and to know the pion properties and aspects of the symmetries of the strong interaction at finite density. We modify the formula of the even-even nuclear target case to study the pionic atom formation spectra on the even-odd nuclear target and show the numerical results of 117Sn target case. This experiment will be performed at RIBF/RIKEN in near future.