CERN Accelerating science

Article
Report number	arXiv:1102.5286
Title	First observation of two hyperfine transitions in antiprotonic $^3$He
Author(s)	Friedreich, S. (Stefan Meyer Inst. Subatomare Phys.) ; Barna, D. (Tokyo U. ; Budapest, RMKI) ; Caspers, F. (CERN) ; Dax, A. (Tokyo U.) ; Hayano, R.S. (Tokyo U.) ; Hori, M. (Tokyo U. ; Munich, Max Planck Inst. Quantenopt.) ; Horvath, D. (Budapest, RMKI ; Debrecen, Inst. Nucl. Res.) ; Juhasz, B. (Stefan Meyer Inst. Subatomare Phys.) ; Kobayashi, T. (Tokyo U.) ; Massiczek, O. (Stefan Meyer Inst. Subatomare Phys.) ; Soter, A. (Munich, Max Planck Inst. Quantenopt.) ; Todoroki, K. (Tokyo U.) ; Widmann, E. (Stefan Meyer Inst. Subatomare Phys.) ; Zmeskal, J. (Stefan Meyer Inst. Subatomare Phys.)
Publication	2011
Imprint	28 Feb 2011
Number of pages	8
Note	Comments: 8 pages, 6 figures, to be published in Physics Letters B 8 pages, 6 figures, just published (online so far) in Physics Letters B
In:	Phys. Lett. B 700 (2011) 1-6
DOI	10.1016/j.physletb.2011.04.029
Subject category	Other Fields of Physics
Accelerator/Facility, Experiment	CERN AD ; ASACUSA AD-3
Abstract	We report on the first experimental results for microwave spectroscopy of the hyperfine structure of antiprotonic He-3. Due to the helium nuclear spin, antiprotonic He-3 has a more complex hyperfine structure than antiprotonic He-4 which has already been studied before. Thus a comparison between theoretical calculations and the experimental results will provide a more stringent test of the three-body quantum electrodynamics (QED) theory. Two out of four super-super-hyperfine (SSHF) transition lines of the (n,L)=(36,34) state were observed. The measured frequencies of the individual transitions are 11.12559(14) GHz and 11.15839(18) GHz, less than 1 MHz higher than the current theoretical values, but still within their estimated errors. Although the experimental uncertainty for the difference of these frequencies is still very large as compared to that of theory, its measured value agrees with theoretical calculations. This difference is important because it is proportional to the magnetic moment of the antiproton.
Copyright/License	Elsevier B.V.

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