Electric quadrupole moments and strong interaction effects in pionic atoms of 165Ho, 175Lu, 176Lu, 179Hf and 181Ta

The effective quadrupole moments Q sub(eff) of the nuclei of 165Ho, 175Lu, 176Lu, 179Hf and 181Ta were accurately measured by detecting the pionic atom 5g-4f x-rays of the elements. The spectroscopic quadrupole moments, Q sub(spec), were obtained by correcting Q sub(eff) for nuclear finite size effect, distortion of the pion wave function by the pion-nucleus strong interaction, and contribution to the energy level splittings by the strong interaction. The intrinsic quadrupole moments, Q0, were obtained by projecting Q sub(spec) into the frame of reference fixed on the nucleus. The shift, epsilon0, and broadening, GAMMA0, of the 4f energy level due to the strong interactions between the pion and the nucleons for all the elements were also measured. Theoretical values of epsilon0 and GAMMA0 were calculated and compared to the experimental values. The measured values of Q0 were compared with the existing results in muonic and pionic atoms. The measured values of epsilon0 and GAMMA0 were also compared with existing values. (auth)