The binding energies of the deeply bound 1s and 2p states in pionic atoms of $^{ 207}$Pb, recently established experimentally in the $^{ 208}$Pb(d,$^3$He) reaction, have been used by several groups to derive the pion effective mass in nuclear matter. We show that these binding energies are fully consistent with `normal' pionic atoms and that the real part of the pion-nucleus potential at the center of $^{ 207}$Pb is 28$\pm$3 MeV and not 20 MeV as suggested previously.
Categories: nucl-th