Measurement of the s-wave contribution to 2 p-level shifts in pionic atoms.

Energies and widths of pionic 3 d-2 p transitions ofZn,Ge, andAs have been measured with a Ge detector. The values of the 2 p shifts obtained from the measurement ε(Zn)=7.0±1.4keV, ε(Ge)=5.5±0.9keV, and ε(As)=4.6±0.9keV show a decreasing behaviour for large Z, which is caused by an increasing s-wave contribution as predicted by theory. [ABSTRACT FROM AUTHOR]