異常磁気モーメント
A 2 = A 2 2 − l o o p ( α π ) 2 + A 2 3 − l o o p ( α π ) 3 + A 2 4 − l o o p ( α π ) 4 + ⋯ {\displaystyle A_{2}=A_{2}^{\mathrm {2-loop} }\left({\frac {\alpha }{\pi }}\right)^{2}+A_{2}^{\mathrm {3-loop} }\left({\frac {\alpha }{\pi }}\right)^{3}+A_{2}^{\mathrm {4-loop} }\left({\frac {\alpha }{\pi }}\right)^{4}+\cdots }
A 3 = A 3 3 − l o o p ( α π ) 3 + A 3 4 − l o o p ( α π ) 4 + A 3 5 − l o o p ( α π ) 5 + ⋯ {\displaystyle A_{3}=A_{3}^{\mathrm {3-loop} }\left({\frac {\alpha }{\pi }}\right)^{3}+A_{3}^{\mathrm {4-loop} }\left({\frac {\alpha }{\pi }}\right)^{4}+A_{3}^{\mathrm {5-loop} }\left({\frac {\alpha }{\pi }}\right)^{5}+\cdots }