Theoretical Response to the Discovery of Deeply Bound Pionic States in 208Pb(d,3He) reactions

Recently, deeply bound pionic states were found experimentally in (d, $^3$He) reactions on $^{208}$Pb. They found an isolated peak structure in the bound region below the pion production threshold. We study theoretically these excitation functions in (d, $^3$He) reactions on $^{208}$Pb at T$_d$=600 MeV. We found very good agreement with the (d, $^3$He) excitation functions and could identify the underlying structures of the pionic states. We study the energy dependence of the (d, $^3$He) reactions and the change of the excitation functions with the incident energy.