Hyperfine structure of antiprotonic helium revealed by a laser-microwave-laser resonance method

E Widmann; J Eades; T Ishikawa; J Sakaguchi; T Tasaki; H Yamaguchi; R S Hayano; M Hori; H A Torii; B Juhász; D Horváth; T Yamazaki

doi:10.1103/PhysRevLett.89.243402

Hyperfine structure of antiprotonic helium revealed by a laser-microwave-laser resonance method

Phys Rev Lett. 2002 Dec 9;89(24):243402. doi: 10.1103/PhysRevLett.89.243402. Epub 2002 Nov 22.

Authors

E Widmann¹, J Eades, T Ishikawa, J Sakaguchi, T Tasaki, H Yamaguchi, R S Hayano, M Hori, H A Torii, B Juhász, D Horváth, T Yamazaki

Affiliation

¹ Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Japan.

PMID: 12484942
DOI: 10.1103/PhysRevLett.89.243402

Abstract

Using a newly developed laser-microwave-laser resonance method, we observed a pair of microwave transitions between hyperfine levels of the (n,L)=(37,35) state of antiprotonic helium. This experiment confirms the quadruplet hyperfine structure arising from the interaction of the antiproton orbital angular momentum, the electron spin and the antiproton spin as predicted by Bakalov and Korobov. The measured frequencies of nu(+)(HF)=12.895 96+/-0.000 34 GHz and nu(-)(HF)=12.924 67+/-0.000 29 GHz agree with recent theoretical calculations on a level of 6x10(-5).