Hyperfine anomalies in Fr: boundaries of the spherical single particle model

J. Zhang, M. Tandecki. R. Collister, S. Aubin +6

We have measured the hyperfine splitting of the $7P_{1/2}$ state at the 100 ppm level in Fr isotopes (${}^{206g,206m,207,209,213,221}$Fr) near the closed neutron shell ($N$ = 126…