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

We consider pionic atom spectroscopy by the (d, ³He) reaction on an odd-neutron nuclear target in this article, which has not yet been investigated. In the (d, ³He) reaction on the odd-neutron nuclear target, we can observe pionic states in the even-neutron nucleus with spin-parity 0⁺. We expect that these pionic states do not have 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 pion-particle plus neutron-hole [π ⊗ n^-1] states. Thus, in addition to widening the domain of pionic atom spectroscopy on the nuclear chart, the present study of the (d, ³He) reaction on an odd-neutron target is considered to be important to deduce extremely precise information on the binding energies of the observed pionic states, and to clarify 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 pionic atom formation spectra on the even–odd nuclear target and show the numerical results of the ¹¹⁷Sn target case. This experiment will be performed at RIBF/RIKEN in the near future. (author)