First Production and Detection of Cold Antihydrogen Atoms
The ATHENA experiment recently produced the first atoms of cold antihydrogen. This paper gives a brief review of how this was achieved.
hep-ex↗
arXiv subjects
R. S. Hayano
Publications and source records attributed to R. S. Hayano.
Precise laser spectroscopy of the antiprotonic helium atom and CPT test on antiproton mass and charge
We have measured twelve transition frequencies of the antiprotonic helium atom (pbar-He+) with precisions of 0.1--0.2 ppm using a laser spectroscopic method. The agreement between the experiment and theories was so good that we can put a limit on the proton-antiproton mass (or charge) difference. The new limit is expected to be much smaller than the already published value, 60 ppb.
nucl-ex↗
Hyperfine structure of antiprotonic helium revealed by a laser-microwave-laser resonance method
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 due to 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 $ν_{\text HF}^+ =12.89596 \pm 0.00034$ GHz and $ν_{\text HF}^- =12.92467 \pm 0.00029$ GHz agree with recent theoretical calculations on a level of $ 6 \times10^{-5}$.
physics.atom-ph↗
Hyperfine Structure Measurements of Antiprotonic Helium and Antihydrogen
This paper describes measurements of the hyperfine structure of two antiprotonic atoms that are planned at the Antiproton Decelerator (AD) at CERN. The first part deals with antiprotonic helium, a three-body system of alpha-particle, antiproton and electron that was previously studied at LEAR. A measurement will test existing three-body calculations and may - through comparison with these theories - determine the magnetic moment of the antiproton more precisely than currently available, thus providing a test of CPT invariance. The second system, antihydrogen, consisting of an antiproton and a positron, is planned to be produced at thermal energies at the AD. A measurement of the ground-state hyperfine splitting, which for hydrogen is one of the most accurately measured physical quantities, will directly yield a precise value for the magnetic moment of the antiproton, and also compare the internal structure of proton and antiproton through the contribution of the magnetic size of the antiproton to the ground state hyperfine splitting.
nucl-ex↗
Formation of $η$-mesic Nuclei Using the Recoilless (d,$^3$He) Reaction
We propose to use the recoilless (d,$^3$He) reaction to produce $η$-mesic nuclei. This reaction has been used to observe deeply bound pionic states and proven to be powerful recently. We calculate $η$-mesic bound states in the nucleus using an optical potential and their formation cross section with the Green function method. Then, we carefully check the experimental feasibility. We find that $η$-mesic nuclei can be observed experimentally using the (d,$^3$He) reaction. We also mention the possibility to study the formation of $ω$-mesic nuclei.
nucl-th↗