Nuclear g factors of the 21 2 − and the 29 2 + states in At 211

The $g$ factors of the ${\frac{21}{2}}^{\ensuremath{-}}$ (1416.3 keV, ${T}_{\frac{1}{2}}=50$ nsec) and the ${\frac{29}{2}}^{+}$ (2641.2 keV, ${T}_{\frac{1}{2}}=70$ nsec) states in $^{211}\mathrm{At}$ were measured by the time differential spin rotation method. The experimental results corrected for diamagnetic shielding and Knight shift are $g({\frac{21}{2}}^{\ensuremath{-}})=+0.917\ifmmode\pm\else\textpm\fi{}0.016$ and $g({\frac{29}{2}}^{+})=+1.073\ifmmode\pm\else\textpm\fi{}0.031$. The analysis yields an orbital $g$ factor of the proton ${g}_{t}=1.12\ifmmode\pm\else\textpm\fi{}0.04$. The comparison with $g$ factors of other ${({h}_{\frac{9}{2}})}^{n}$ proton states in $N=126$ isotones shows a significant deviation from the predicted blocking of core polarization.