Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon
T. Okumura, T. Azuma, D. A. Bennett, I. Chiu, W. B. Doriese, Malcolm Durkin, J. W. Fowler, Johnathon D. Gard, T. Hashimoto, R. Hayakawa, G. C. Hilton, Yuto Ichinohe, P. Indelicato, T. Isobe, S. Kanda, M. Katsuragawa, N. Kawamura, Yasushi Kino, Kairi Mine, Yasuhiro Miyake, Kelsey M. Morgan, Kazuhiko Ninomiya, Hirofumi Noda, G. C. O’Neil, S. Okada, Kenichi Okutsu, N. Paul, C. D. Reintsema, Daniel R. Schmidt, K. Shimomura, P. Strasser, H. Suda, Daniel S. Swetz, Tadayuki Takahashi, Shin’ichiro Takeda, Soshi Takeshita, M. Tampo, H. Tatsuno, Y. Ueno, Joel N. Ullom, Shin Watanabe, S. Yamada
Abstract
To test bound-state quantum electrodynamics (BSQED) in the strong-field regime, we have performed high precision x-ray spectroscopy of the 5g-4f and 5f- 4d transitions (BSQED contribution of 2.4 and 5.2 eV, respectively) of muonic neon atoms in the low-pressure gas phase without bound electrons. Muonic atoms have been recently proposed as an alternative to few-electron high-Z ions for BSQED tests by focusing on circular Rydberg states where nuclear contributions are negligibly small. We determined the 5g_{9/2}- 4f_{7/2} transition energy to be 6297.08±0.04(stat)±0.13(syst) eV using superconducting transition-edge sensor microcalorimeters (5.2-5.5 eV FWHM resolution), which agrees well with the most advanced BSQED theoretical prediction of 6297.26 eV.