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 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

scholarly journals Two-photon laser spectroscopy of antiprotonic helium and the antiproton-electron mass ratio

2013 ◽  
Author(s):  
D. Barna ◽  
M. Hori ◽  
A. Sótér ◽  
A. Dax ◽  
R. Hayano ◽  
...  
Keyword(s):  
Laser Spectroscopy ◽  
Antiprotonic Helium ◽  
Electron Mass ◽  
Mass Ratio ◽  
Two Photon

Sub-Doppler Two-Photon Laser Spectroscopy of Antiprotonic Helium and the Antiproton-to-Electron Mass Ratio

2013 ◽  
Vol 54 (7-10) ◽  
pp. 917-922
Author(s):  
M. Hori ◽  
A. Sótér ◽  
D. Barna ◽  
A. Dax ◽  
R. S. Hayano ◽  
...  
Keyword(s):  
Laser Spectroscopy ◽  
Antiprotonic Helium ◽  
Electron Mass ◽  
Mass Ratio ◽  
Two Photon

scholarly journals Recent progress of laser spectroscopy experiments on antiprotonic helium

2018 ◽  
Vol 376 (2116) ◽  
pp. 20170270 ◽  
Author(s):  
Masaki Hori
Keyword(s):  
Laser Spectroscopy ◽  
Quantum Electrodynamics ◽  
Single Photon ◽  
Atomic Spectroscopy ◽  
Antiprotonic Helium ◽  
Doppler Width ◽  
Electron Mass ◽  
Spectroscopic Techniques ◽  
Buffer Gas ◽  
Mass Ratio

The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) collaboration is currently carrying out laser spectroscopy experiments on antiprotonic helium atoms at CERN’s Antiproton Decelerator facility. Two-photon spectroscopic techniques have been employed to reduce the Doppler width of the measured resonance lines, and determine the atomic transition frequencies to a fractional precision of 2.3–5 parts in 10 9 . More recently, single-photon spectroscopy of buffer-gas cooled has reached a similar precision. By comparing the results with three-body quantum electrodynamics calculations, the antiproton-to-electron mass ratio was determined as , which agrees with the known proton-to-electron mass ratio with a precision of 8×10 −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’.

Weighing the antiproton by parts-per-billion-scale laser spectroscopy of antiprotonic helium

2007 ◽  
Vol 85 (5) ◽  
pp. 453-460 ◽  
Author(s):  
R S Hayano
Keyword(s):  
Laser Spectroscopy ◽  
Continuous Wave ◽  
Frequency Comb ◽  
Antiprotonic Helium ◽  
Electron Mass ◽  
Helium Nucleus ◽  
Body System ◽  
Mass Ratio ◽  
14.20 Dh ◽  
Three Body

A femtosecond optical frequency comb and continuous-wave pulse-amplified laser were used to measure 12 transition frequencies of antiprotonic helium (metastable three-body system consisting of an antiproton, an electron, and a helium nucleus) to fractional precisions of (9–16) × 10–9. One of these is between two states having microsecond-scale lifetimes hitherto unaccessible to our precision laser spectroscopy method. Comparisons with three-body QED calculations yielded an antiproton-to-electron mass ratio of [Formula: see text] = 1836.152 674(5).PACS Nos.: 36.10.–k, 14.20.Dh, 32.70.Jz

scholarly journals Two-photon laser spectroscopy of antiprotonic helium and the antiproton-to-electron mass ratio

Nature ◽  
2011 ◽  
Vol 475 (7357) ◽  
pp. 484-488 ◽  
Author(s):  
Masaki Hori ◽  
Anna Sótér ◽  
Daniel Barna ◽  
Andreas Dax ◽  
Ryugo Hayano ◽  
...  
Keyword(s):  
Laser Spectroscopy ◽  
Antiprotonic Helium ◽  
Electron Mass ◽  
Mass Ratio ◽  
Two Photon
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