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 ◽  
...  
2014 ◽  
Vol 66 ◽  
pp. 05020
Author(s):  
A. Sótér ◽  
M. Hori ◽  
D. Barna ◽  
R. Hayano ◽  
A. Dax ◽  
...  

2013 ◽  
Vol 54 (7-10) ◽  
pp. 917-922
Author(s):  
M. Hori ◽  
A. Sótér ◽  
D. Barna ◽  
A. Dax ◽  
R. S. Hayano ◽  
...  

2013 ◽  
Vol 22 (09) ◽  
pp. 1330024
Author(s):  
MASAKI HORI

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.


Nature ◽  
2011 ◽  
Vol 475 (7357) ◽  
pp. 484-488 ◽  
Author(s):  
Masaki Hori ◽  
Anna Sótér ◽  
Daniel Barna ◽  
Andreas Dax ◽  
Ryugo Hayano ◽  
...  

2018 ◽  
Vol 181 ◽  
pp. 01001
Author(s):  
Masaki Hori

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.


Author(s):  
Masaki Hori

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’.


2007 ◽  
Vol 85 (5) ◽  
pp. 453-460 ◽  
Author(s):  
R S Hayano

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


Science ◽  
2020 ◽  
Vol 369 (6508) ◽  
pp. 1238-1241 ◽  
Author(s):  
Sayan Patra ◽  
M. Germann ◽  
J.-Ph. Karr ◽  
M. Haidar ◽  
L. Hilico ◽  
...  

Recent mass measurements of light atomic nuclei in Penning traps have indicated possible inconsistencies in closely related physical constants such as the proton-electron and deuteron-proton mass ratios. These quantities also influence the predicted vibrational spectrum of the deuterated molecular hydrogen ion (HD+) in its electronic ground state. We used Doppler-free two-photon laser spectroscopy to measure the frequency of the v = 0→9 overtone transition (v, vibrational quantum number) of this spectrum with an uncertainty of 2.9 parts per trillion. By leveraging high-precision ab initio calculations, we converted our measurement to tight constraints on the proton-electron and deuteron-proton mass ratios, consistent with the most recent Penning trap determinations of these quantities. This results in a precision of 21 parts per trillion for the value of the proton-electron mass ratio.


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