International Conference on Exotic Atoms and Related Topics - EXA2017

Precision hyperfine spectroscopy of antihydrogen is one of the primary goals of the ALPHA experiment. In hydrogen, the zero-field ground-state hyperfine splitting frequency has been measured to better than 1 part in 10^12 [1]. A measurement of a similar precision on antihydrogen would provide an extremely precise test of CPT symmetry. An initial proof-of-principle experiment was performed in 2012 demonstrating the ability to excite positron spin resonance transitions in ground state antihydrogen [2]. In this talk, I will present the tools we have developed to study antihydrogen's hyperfine structure and the results of ALPHA's latest hyperfine spectroscopy experiments. [1] IEEE Trans. Instrum. Meas. IM-19, 200 (1970); Nature 229 110 (1970). [2] Amole et al., Nature 483, 439 (2012).