© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

arXiv:physics/0207059 · Physical Review Letters

Hyperfine Structure of Antiprotonic Helium Revealed by a Laser-Microwave-Laser Resonance Method

E. Widmann, J. A. Eades, Takashi Ishikawa, Jun Sakaguchi, T. Tasaki, H. Yamaguchi, R. Hayano, M. Hori, H. A. Torii, Bertalan Juhász, D. Horváth, Toshitsugu Yamazaki

Published Nov 22, 2002• 59 citations

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 ${\ensuremath{\nu}}_{\mathrm{H}\mathrm{F}}^{+}=12.895\text{ }96\ifmmode\pm\else\textpm\fi{}0.000\text{ }34\text{ }\mathrm{G}\mathrm{H}\mathrm{z}$ and ${\ensuremath{\nu}}_{\mathrm{H}\mathrm{F}}^{\ensuremath{-}}=12.924\text{ }67\ifmmode\pm\else\textpm\fi{}0.000\text{ }29\text{ }\mathrm{G}\mathrm{H}\mathrm{z}$ agree with recent theoretical calculations on a level of $6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$.

DOI: 10.1103/physrevlett.89.243402

Related papers

Coupled-channel analysis of collisional effects on HFS transitions in antiprotonic helium atoms

Grigory Ya. Korenman, S. N. Yudin

Collisions of metastable antiprotonic helium with atoms of a medium induce transitions between hyperfine structure sublevels as well as shifts and broadenings of the microwave M1 spectral lines. We consider these phenomena in the framework of a model with scalar and tensor interactions between and He atoms. S -matrix is obtained by solving coupled-channels equations involving 4 HFS sublevels ( F = L ± 1/2, J = F ± 1/2) of the nL level and relative angular momenta up to l = 5 at the kinetic energy E ≲ 25 K. The inelastic cross sections are less than elastic ones by four orders of value for the single electron or antiproton spin-flip transitions (Δ J = ±1, Δ F = 0, ± 1) and by seven orders of value for the double spin-flip transitions (Δ J = 0, ± 2, Δ F = ±1). The cross sections show a resonance behaviour at very low energy ( E ∼ 1–4 K). The results for the relaxation rate λ( F − → F + ), the frequency shift and broadening of the M1 spectral lines for the favoured transitions (Δ F = ±1, Δ J = ±1) are compatible with the recent experimental data obtained by a triple (laser–microwave–laser) resonance method at T = 6 K. The calculated values are lowered by a factor of 1.5–2 with the temperature rising up to 25 K.

arXiv:nucl-th/0411077•Journal of Physics B Atomic Molecular and Optical Physics•Mar 6, 2006•21 citations

Coupled rearrangement channel calculation of the fine and hyperfine structures of the antiprotonic helium atom - art. no. 012518

Noriaki Yamanaka, Yasushi Kino, Hiroshi Kudo +1 more

We precisely calculate the fine and hyperfine structure splittings of the (v,J) = (1,35) state in the antiprotonic helium atom, when v is the vibrational quantum number and J is the total orbital angular momentum. The coupled rearrangement channel method

Physical Review A•Jan 1, 2001•6 citations

Spin-orbit corrections of order mα6 to the fine structure of the (37,35) state in the H4e p¯ antiprotonic helium atom

V. I. Korobov, Zhen-Xiang Zhong

Precise numerical calculation of radiofrequency intervals between hyperfine sublevels of the (37,35) state of the antiprotonic helium-4 atom is presented. Theoretical consideration includes the QED corrections of order $m{\ensuremath{\alpha}}^{6}$ to the electron spin-orbit interaction. Only the leading order contribution in the electron-to-antiproton and electron-to-$\ensuremath{\alpha}$ particle mass ratios is considered, so the $\ensuremath{\alpha}$ particle and antiproton are treated nonrelativistically. The effective Hamiltonian is derived using the formalism of the nonrelativistic quantum electrodynamics.

arXiv:0908.1482•Physical Review A•Oct 14, 2009•8 citations

Coupled rearrangement channel calculation of the fine and hyperfine structures of the antiprotonic helium atom

Nobuhiro Yamanaka, Yasushi Kino, Hiroshi Kudo +1 more

We precisely calculate the fine and hyperfine structure splittings of the $(v,J)=(1,35)$ state in the antiprotonic helium atom, where $v$ is the vibrational quantum number and $J$ is the total orbital angular momentum. The coupled rearrangement channel method is employed to efficiently describe correlation effects in the three-body system with atomic and molecular characters. An accuracy of better than ${\ensuremath{\alpha}}^{2}\ensuremath{\approx}50\mathrm{ppm}$ has been achieved. The result obtained is in good agreement with the previous calculation within $\ensuremath{\sim}200 \mathrm{ppm}.$ We also examine the correlation effects, in particular orbital polarization effects.

Physical Review A•Dec 13, 2000•34 citations

Laser Studies of the Decay Chain of Metastable Antiprotonic Helium Atoms

R. Hayano, Frank E. Maas, H. A. Torii +14 more

Laser studies of metastable antiprotonic helium atoms, which we recently initiated by observing a sharp increase of the antiproton annihilation rate induced by laser-stimulated resonant transitions, have been extended. With a single laser tuned to the resonance already found at 597.26 nm, we have now established the time dependence of the upper state population. With two lasers ignited at variable time separation, we also studied the feeding of the upper state from higher atomic levels. The initial populations and level lifetimes of excited exotic atoms were determined.

Physical Review Letters•Sep 12, 1994•63 citations

Observation of double-resonant laser-induced transitions in the v=n-l-1=2 metastable cascade of antiprotonic He4 atoms

R. Hayano, Takashi Ishikawa, Hitomi Tamura +15 more

Another laser-induced resonant transition in the v=n-l-1=2 metastable cascade of antiprotonic $^{4}\mathrm{He}$ atoms has been found by using a double-resonance technique. This was done by setting the first laser to the already known 470.724-nm resonance [(n,l)=(37,34)\ensuremath{\rightarrow}(36,33)], while the (38,35)\ensuremath{\rightarrow}(37,34) transition was searched for with the second laser. The resonant transition was found at a wavelength of 529.622\ifmmode\pm\else\textpm\fi{}0.003 nm, showing excellent agreement with a recent prediction of Korobov.

Physical Review A•Jan 1, 1997•34 citations

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

{\ensuremath{\nu}}_{\mathrm{H}\mathrm{F}}^{+}=12.895\text{ }96\ifmmode\pm\else\textpm\fi{}0.000\text{ }34\text{ }\mathrm{G}\mathrm{H}\mathrm{z}

and

{\ensuremath{\nu}}_{\mathrm{H}\mathrm{F}}^{\ensuremath{-}}=12.924\text{ }67\ifmmode\pm\else\textpm\fi{}0.000\text{ }29\text{ }\mathrm{G}\mathrm{H}\mathrm{z}

agree with recent theoretical calculations on a level of

6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}

.

Collisions of metastable antiprotonic helium with atoms of a medium induce transitions between hyperfine structure sublevels as well as shifts and broadenings of the microwave M1 spectral lines. We consider these phenomena in the framework of a model with scalar and tensor interactions between and He atoms. S -matrix is obtained by solving coupled-channels equations involving 4 HFS sublevels ( F = L ± 1/2, J = F ± 1/2) of the nL level and relative angular momenta up to l = 5 at the kinetic energy E ≲ 25 K. The inelastic cross sections are less than elastic ones by four orders of value for the single electron or antiproton spin-flip transitions (Δ J = ±1, Δ F = 0, ± 1) and by seven orders of value for the double spin-flip transitions (Δ J = 0, ± 2, Δ F = ±1). The cross sections show a resonance behaviour at very low energy ( E ∼ 1–4 K). The results for the relaxation rate λ( F − → F + ), the frequency shift and broadening of the M1 spectral lines for the favoured transitions (Δ F = ±1, Δ J = ±1) are compatible with the recent experimental data obtained by a triple (laser–microwave–laser) resonance method at T = 6 K. The calculated values are lowered by a factor of 1.5–2 with the temperature rising up to 25 K.

Precise numerical calculation of radiofrequency intervals between hyperfine sublevels of the (37,35) state of the antiprotonic helium-4 atom is presented. Theoretical consideration includes the QED corrections of order $m{\ensuremath{\alpha}}^{6}$ to the electron spin-orbit interaction. Only the leading order contribution in the electron-to-antiproton and electron-to-$\ensuremath{\alpha}$ particle mass ratios is considered, so the $\ensuremath{\alpha}$ particle and antiproton are treated nonrelativistically. The effective Hamiltonian is derived using the formalism of the nonrelativistic quantum electrodynamics.

We precisely calculate the fine and hyperfine structure splittings of the

(v,J)=(1,35)

state in the antiprotonic helium atom, where

v

is the vibrational quantum number and

J

is the total orbital angular momentum. The coupled rearrangement channel method is employed to efficiently describe correlation effects in the three-body system with atomic and molecular characters. An accuracy of better than ${\ensuremath{\alpha}}^{2}\ensuremath{\approx}50\mathrm{ppm}$ has been achieved. The result obtained is in good agreement with the previous calculation within $\ensuremath{\sim}200 \mathrm{ppm}.$ We also examine the correlation effects, in particular orbital polarization effects.

Laser studies of metastable antiprotonic helium atoms, which we recently initiated by observing a sharp increase of the antiproton annihilation rate induced by laser-stimulated resonant transitions, have been extended. With a single laser tuned to the resonance already found at 597.26 nm, we have now established the time dependence of the upper state population. With two lasers ignited at variable time separation, we also studied the feeding of the upper state from higher atomic levels. The initial populations and level lifetimes of excited exotic atoms were determined.

Another laser-induced resonant transition in the v=n-l-1=2 metastable cascade of antiprotonic

^{4}\mathrm{He}

atoms has been found by using a double-resonance technique. This was done by setting the first laser to the already known 470.724-nm resonance [(n,l)=(37,34)\ensuremath{\rightarrow}(36,33)], while the (38,35)\ensuremath{\rightarrow}(37,34) transition was searched for with the second laser. The resonant transition was found at a wavelength of 529.622\ifmmode\pm\else\textpm\fi{}0.003 nm, showing excellent agreement with a recent prediction of Korobov.