Precision Microwave Spectroscopy of the Positronium n=2 Fine Structure.
PHYSICAL REVIEW LETTERS 2020;
125:073002. [PMID:
32857572 DOI:
10.1103/physrevlett.125.073002]
[Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
We report a new measurement of the positronium (Ps) 2^{3}S_{1}→2^{3}P_{0} interval. Slow Ps atoms, optically excited to the radiatively metastable 2^{3}S_{1} level, flew through a microwave radiation field tuned to drive the transition to the short-lived 2^{3}P_{0} level, which was detected via the time spectrum of subsequent ground state Ps annihilation radiation. After accounting for Zeeman shifts we obtain a transition frequency ν_{0}=18501.02±0.61 MHz, which is not in agreement with the theoretical value of ν_{0}=18498.25±0.08 MHz.
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