Sign of the g factor of the 4₁⁺ state in ⁶⁸Zn

In two recent papers a negative g factor was reported for the 4₁⁺ state in ⁶⁸Zn. The negative sign is unexpected. It is not consistent with the systematics of g factors in the neighboring Zn and Ge isotopes and could not be explained by shell-model calculations even when significant contributions of the 0g_9/2 neutrons were included. Therefore, an independent g factor measurement was performed, using ⁶⁸Zn projectiles which were accelerated to a higher energy in order to obtain a higher yield for the 4₁⁺ state. The new measurement yielded a positive g factor, g(4₁⁺)=+0.6(3), which agrees with the results of full fp spherical shell model calculations, as well as with Z/A, the collective model prediction.