Leading term of the He-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mover accent="true"><mml:mi>p</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:msup><mml:mrow><mml:mi>He</mml:mi></mml:mrow><mml:mo>+</mml:mo></mml:msup></mml:mrow></mml:math>long-range interaction

Korobov, V. I.; Zhong, Zhen-Xiang; Tian, Qian

doi:10.1103/physreva.92.052517

Cited by 10 publications

(6 citation statements)

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“…One possibility is that collisions with other helium atoms may destroy the π − population that occupies the parent state (n, ) = (16, 15). Similar effects have been observed in several states of pHe + atoms [62][63][64][65]. Alternatively, it may be that only a negligible fraction of π − are captured into state (n, ) = (16, 15), as has been observed for some states of lower n in the pHe + case [66][67][68][69].…”

Section: Resultssupporting

confidence: 73%

Recent results of laser spectroscopy experiments of pionic helium atoms at PSI

Hori

Sótér

Barna

et al. 2021

SciPost Phys. Proc.

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Section: Resultssupporting

confidence: 73%

Recent results of laser spectroscopy experiments of pionic helium atoms at PSI

Hori

Sótér

Barna

et al. 2021

SciPost Phys. Proc.

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“…The spectral resolutions are an order of magnitude higher than the limits that would be expected according to the predictions of ab initio theoretical calculations for atoms of temperature T ≈ 5.4 K using the impact approximation of binary collisions 17 , 18 , which were based on pairwise potentials derived from the highly precise wavefunctions of (refs. 7 , 38 ). Taken together with the abrupt narrowing observed at T λ , this implies that collective effects in the superfluid narrow the laser resonances below the limit expected from simple binary atomic collisions.…”

Section: Mainmentioning

confidence: 99%

High-resolution laser resonances of antiprotonic helium in superfluid 4He

Sótér

Aghai-Khozani

Barna

et al. 2022

Nature

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When atoms are placed into liquids, their optical spectral lines corresponding to the electronic transitions are greatly broadened compared to those of single, isolated atoms. This linewidth increase can often reach a factor of more than a million, obscuring spectroscopic structures and preventing high-resolution spectroscopy, even when superfluid helium, which is the most transparent, cold and chemically inert liquid, is used as the host material1–6. Here we show that when an exotic helium atom with a constituent antiproton7–9 is embedded into superfluid helium, its visible-wavelength spectral line retains a sub-gigahertz linewidth. An abrupt reduction in the linewidth of the antiprotonic laser resonance was observed when the liquid surrounding the atom transitioned into the superfluid phase. This resolved the hyperfine structure arising from the spin–spin interaction between the electron and antiproton with a relative spectral resolution of two parts in 106, even though the antiprotonic helium resided in a dense matrix of normal matter atoms. The electron shell of the antiprotonic atom retains a small radius of approximately 40 picometres during the laser excitation7. This implies that other helium atoms containing antinuclei, as well as negatively charged mesons and hyperons that include strange quarks formed in superfluid helium, may be studied by laser spectroscopy with a high spectral resolution, enabling the determination of the particle masses9. The sharp spectral lines may enable the detection of cosmic-ray antiprotons10,11 or searches for antideuterons12 that come to rest in liquid helium targets.

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“…Stark mixing during collisions with other helium atoms does not easily occur because the antiprotonic states having the same n-value are far from degenerate in this threebody system. The 1s electron protects the antiproton during collisions with other helium atoms in the target [21,22]. The metastablepHe + preferentially deexcites by undergoing slow radiative transitions of the type n = = −1 with lifetimes of τ = 1-2 µs.…”

Section: Introductionmentioning

confidence: 99%

Recent progress of laser spectroscopy experiments on antiprotonic helium

Hori¹

2018

Phil. Trans. R. Soc. A.

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The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) collaboration is currently carrying out laser spectroscopy experiments on antiprotonic helium [Formula: see text] atoms at CERN's Antiproton Decelerator facility. Two-photon spectroscopic techniques have been employed to reduce the Doppler width of the measured [Formula: see text] resonance lines, and determine the atomic transition frequencies to a fractional precision of 2.3-5 parts in 10 More recently, single-photon spectroscopy of buffer-gas cooled [Formula: see text] has reached a similar precision. By comparing the results with three-body quantum electrodynamics calculations, the antiproton-to-electron mass ratio was determined as [Formula: see text], which agrees with the known proton-to-electron mass ratio with a precision of 8×10 The high-quality antiproton beam provided by the future Extra Low Energy Antiproton Ring (ELENA) facility should enable further improvements in the experimental precision.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.

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Leading term of the He-p¯He+long-range interaction

Cited by 10 publications

References 42 publications

Recent results of laser spectroscopy experiments of pionic helium atoms at PSI

Recent results of laser spectroscopy experiments of pionic helium atoms at PSI

High-resolution laser resonances of antiprotonic helium in superfluid 4He

Recent progress of laser spectroscopy experiments on antiprotonic helium

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