Energy of the ${}^{229}$Th Nuclear Clock Isomer Determined by Absolute $\gamma$-ray Energy Difference

A. Yamaguchi, H. Muramatsu, T. Hayashi +10

The low-lying isomeric state of ${}^{229}$Th provides unique opportunities for high-resolution laser spectroscopy of the atomic nucleus. We determine the energy of this isomeric stat…