The magnetic moment anomaly of the electron bound in hydrogenic ions.

The measurement of the g factor of the electron bound in a hydrogenic ion is a high-accuracy test of the theory of Quantum Electrodynamics (QED) in strong fields. Here we report on the measurement of the g factor of the bound electron in hydrogenic carbon ([sup 12]C[sup 5+]). In our experiment a single [sup 12]C[sup 5+] ion is stored in a Penning trap. The electronic spin state of the ion is monitored via the continuous SternGerlach effect in a quantum non-demolition measurement. Quantum jumps between the two spin states (spin up and spin down) are induced by a microwave field at the spin precession frequency of the bound electron. The g factor of the bound electron is obtained by varying the microwave frequency and counting the number of spin flips. The comparison of our experimental value for the g factor of the bound electron, g[sub exp]([sup 12]C[sup 5+]) = 2,001 041 596 (5), with the theoretical value of gth = 2.001 041 591 (7) shows excellent agreement and confirms the recent non-perturbative calculations by T. Beier et al. [ABSTRACT FROM AUTHOR]