Sheldon, RE;
Babij, TJ;
Reeder, SH;
Hogan, SD;
Cassidy, DB;
(2023)
Microwave spectroscopy of positronium atoms in free space.
Physical Review A
, 107
(4)
, Article 042810. 10.1103/physreva.107.042810.
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Abstract
We report measurements of the positronium (Ps) 2 3 S 1 → 2 3 P 2 interval in which atoms traveling in free space were irradiated with microwave radiation generated using a horn antenna. Previous measurements of this transition, performed using atoms in waveguides, exhibited asymmetric and shifted line shapes. In the free-space measurements we report here, much smaller line-shape asymmetry was observed, but with large frequency shifts that varied with the orientation of the horn antenna. Our observations are supported by line-shape simulations and demonstrate that variations in the microwave radiation field distribution can perturb measured line shapes and give rise to apparent frequency shifts without necessarily causing large asymmetries; this effect can explain previous measurements in which an apparent discrepancy with predictions from quantum electrodynamics was ob- served [L. Gurung, T. J. Babij, S. D. Hogan, and D. B. Cassidy, Phys. Rev. Lett. 125, 073002 (2020)].
| Type: | Article |
|---|---|
| Title: | Microwave spectroscopy of positronium atoms in free space |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/physreva.107.042810 |
| Publisher version: | https://doi.org/10.1103/PhysRevA.107.042810 |
| Language: | English |
| Additional information: | Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10168858 |
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