We report measurements of the electric dipole matrix elements of the $^{ 133}$Cs $\ $ $6s\,^2S_{ 1/2} \rightarrow 7p\,^2P_{ 1/2}$ and $6s\,^2S_{ 1/2} \rightarrow 7p\,^2P_{ 3/2}$ transitions. Each of these determinations is based on direct, precise comparisons of the absorption coefficients between two absorption lines. For the $\langle 6s\,^2S_{ 1/2}||r|| 7p\,^2P_{ 3/2} \rangle$ matrix element, we measure the ratio of the absorption coefficient on this line with that of the D$_1$ transition, $6s\,^2S_{ 1/2} \rightarrow 6p\,^2P_{ 1/2}$. The matrix element of the D$_1$ line has been determined with high precision previously by many groups. For the $\langle 6s\,^2S_{ 1/2}||r|| 7p\,^2P_{ 1/2} \rangle$ matrix element, we measure the ratio of the absorption coefficient on this line with that of the $6s\,^2S_{ 1/2} \rightarrow 7p\,^2P_{ 3/2}$ transition. Our results for these matrix elements are $\langle 6s\,^2S_{ 1/2}||r|| 7p\,^2P_{ 3/2} \rangle = 0.57417 \: (57)~a_0$ and $\langle 6s\,^2S_{ 1/2}||r|| 7p\,^2P_{ 1/2} \rangle = 0.27810 \: (45)~a_0$. These measurements have implications for the interpretation of parity nonconservation in atoms.
Categories: physics.atom-ph