Nuclear Quadrupole Effects in Deeply Bound Pionic Atoms

Abstract

We have studied nuclear quadrupole deformation effects in deeply bound pionic atoms theoretically. We have evaluated the level shifts and widths of the hyperfine components using the first order perturbation theory and compared them with the effects of neutron skin. We conclude that the nuclear quadrupole deformation effects for deeply bound $1s$ and $2p$ states are very difficult to observe and that the effects could be observed for $3d$ states. We also conclude that the deformation effects are sensitive to the parameters of the pion-nucleus optical potential.