scholarly journals Laser Spectroscopy Measurements of Metastable Pionic Helium Atoms at Paul Scherrer Institute

2021 ◽  
Vol 62 (3) ◽  
Author(s):  
M. Hori ◽  
H. Aghai-Khozani ◽  
A. Sótér ◽  
A. Dax ◽  
D. Barna
Keyword(s):  
Laser Spectroscopy ◽  
Charged Pion ◽  
Pion Mass ◽  
Precise Determination ◽  
Paul Scherrer Institute ◽  
Antiprotonic Helium ◽  
Helium Atoms ◽  
Three Body ◽  
Paul Scherrer

AbstractWe review recent experiments carried out by the PiHe collaboration of the Paul Scherrer Institute (PSI) that observed an infrared transition of three-body pionic helium atoms by laser spectroscopy. These measurements may lead to a precise determination of the charged pion mass, and complement experiments of antiprotonic helium atoms carried out at the new ELENA facility of CERN.

Laser spectroscopy of antiprotonic helium atoms and ions

2005 ◽  
Vol 83 (4) ◽  
pp. 357-361 ◽  
Author(s):  
R S Hayano
Keyword(s):  
Laser Spectroscopy ◽  
Antiprotonic Helium ◽  
Helium Nucleus ◽  
Low Density ◽  
Body System ◽  
Helium Atoms ◽  
Gas Target ◽  
Helium Gas ◽  
Three Body

Laser spectroscopy of an antiprotonic helium ([Formula: see text]He+) atom, a neutral three-body Coulomb system consisting of an antiproton, a helium nucleus, and an electron has so far contributed to the determination of antiproton mass and charge to a precision of 10-8. Recently, we have succeeded in producing long-lived (τ [Formula: see text] 100 ns) antiprotonic helium ions (two-body system: [Formula: see text]He++). This was done by stopping ∼50 keV antiprotons decelerated by using an "inverse linac" (RFQD) in a very low-density helium gas target and selectively populating the ionic level by using laser tagging. It may be possible to use this two-body ion for future high-precision work.PACS Nos.: 36.10.–k, 34.90.+q, 25.43.+t

TWO-PHOTON LASER SPECTROSCOPY OF ANTIPROTONIC HELIUM

2013 ◽  
Vol 22 (09) ◽  
pp. 1330024
Author(s):  
MASAKI HORI
Keyword(s):  
Laser Spectroscopy ◽  
Quantum Electrodynamics ◽  
Spectral Lines ◽  
Antiprotonic Helium ◽  
Electron Mass ◽  
Doppler Broadening ◽  
Mass Ratio ◽  
Helium Atoms ◽  
Two Photon ◽  
Three Body

The ASACUSA collaboration of CERN has recently carried out two-photon laser spectroscopy of antiprotonic helium atoms. Some nonlinear two-photon transitions of the antiproton at the deep UV wavelengths λ = 139.8–197.0 nm were excited by irradiating the atom with two counterpropagating laser beams. This reduced the thermal Doppler broadening in the observed spectral lines. Three transition frequencies were thus determined with fractional precisions of 2.3–5 parts in 109. By comparing the results with three-body quantum electrodynamics calculations, the antiproton-to-electron mass ratio was derived as 1836.1526736(23). In this paper, we briefly review these recent experimental results.

scholarly journals Precision laser spectroscopy experiments on antiprotonic helium

2018 ◽  
Vol 181 ◽  
pp. 01001
Author(s):  
Masaki Hori
Keyword(s):  
Laser Spectroscopy ◽  
Quantum Electrodynamics ◽  
Single Photon ◽  
Antiprotonic Helium ◽  
Doppler Width ◽  
Electron Mass ◽  
Buffer Gas ◽  
Mass Ratio ◽  
Buffer Gas Cooling ◽  
Three Body

At CERN‘s Antiproton Decelerator (AD) facility, the Atomic Spectroscopyand Collisions Using Slow Antiprotons (ASACUSA) collaboration is carrying out precise laser spectroscopy experiments on antiprotonic helium (p̅He+ ≡ p̅+He2++e−) atoms. By employing buffer-gas cooling techniquesin a cryogenic gas target, samples of atoms were cooled to temperatureT = 1.5–1.7 K, thereby reducing the Doppler width in the single-photon resonance lines. By comparing the results with three-body quantum electrodynamics calculations, the antiproton-to-electron mass ratio was determined as Mp̅/me = 1836.1526734(15). This agreed with the known proton-to-electron mass ratio with a precision of 8 . 1010. Further improvements in the experimental precision are currently being attempted. The high-quality antiproton beam provided by the future Extra Low Energy Antiproton Ring (ELENA) facility should further increase the experimental precision.

scholarly journals Near-infrared laser spectroscopy of antiprotonic helium atoms

2014 ◽  
Vol 66 ◽  
pp. 05010
Author(s):  
T. Kobayashi ◽  
D. Barna ◽  
R. S. Hayano ◽  
Y. Murakami ◽  
K. Todoroki ◽  
...  
Keyword(s):  
Laser Spectroscopy ◽  
Near Infrared ◽  
Infrared Laser ◽  
Antiprotonic Helium ◽  
Helium Atoms ◽  
Infrared Laser Spectroscopy

scholarly journals Antiproton–to–electron mass ratio determined by two-photon laser spectroscopy of antiprotonic helium atoms

2014 ◽  
Vol 66 ◽  
pp. 05020
Author(s):  
A. Sótér ◽  
M. Hori ◽  
D. Barna ◽  
R. Hayano ◽  
A. Dax ◽  
...  
Keyword(s):  
Laser Spectroscopy ◽  
Antiprotonic Helium ◽  
Electron Mass ◽  
Mass Ratio ◽  
Helium Atoms ◽  
Two Photon

EXOTIC HELIUM ATOMS

2010 ◽  
Vol 19 (12) ◽  
pp. 2586-2593
Author(s):  
R. S. Hayano
Keyword(s):  
Laser Spectroscopy ◽  
Recent Progress ◽  
Historical Background ◽  
Antiprotonic Helium ◽  
Past Study ◽  
Future Prospects ◽  
X Ray ◽  
Helium Atoms

Recent progress on the precision laser spectroscopy of antiprotonic helium atoms, as well as on the x-ray spectroscopy of kaonic helium atoms are presented. These two may appear to be unrelated topics (except for the fact that both being exotic helium atoms), but in fact a past study of kaonic helium system led to the serendipitous discovery of antiprotonic helium. Some historical background connecting these two exotic helium atoms, as well as future prospects are discussed.

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