Natural widths of hypersatellite K-X-ray lines and lifetimes of double K-hole states in mid-Z atoms

K-X-ray spectra of Zr, Nb, Mo and Pd targets bombarded with 250 MeV carbon and 360 MeV oxygen ions are studied with high resolution diffraction spectrometry. Relative yields and natural widths of the Khα1,2 hypersatellite lines are determined and compared with those of the diagram lines. The widths of Khα1,2 lines are compared with the new phenomenological formula which takes into account the retardation of the Khα1 transition in the LS coupling scheme. The data significantly exceed the expected values. Deduced lifetimes of the double K-hole states are shorter than expected.