LASER SPECTROSCOPY OF ANTIPROTONIC HELIUM AT CERN'S ANTIPROTON DECELERATOR FACILITY

Author(s):  
M. HORI
2011 ◽  
Vol 89 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Masaki Hori

The ASACUSA collaboration at CERN has previously measured the optical transition frequencies of antiprotonic helium to a precision of <1 part in 108 by laser spectroscopy. We describe some recent theoretical and experimental developmental work carried out by our collaboration to further improve the experimental precision.


2000 ◽  
Vol 663-664 ◽  
pp. 955c-958c
Author(s):  
R.S. Hayano ◽  
J. Eades ◽  
T. von Egidy ◽  
F.J. Hartmann ◽  
M. Hori ◽  
...  

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.


2014 ◽  
Vol 66 ◽  
pp. 05010
Author(s):  
T. Kobayashi ◽  
D. Barna ◽  
R. S. Hayano ◽  
Y. Murakami ◽  
K. Todoroki ◽  
...  

2005 ◽  
Vol 83 (4) ◽  
pp. 357-361 ◽  
Author(s):  
R S Hayano

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


2001 ◽  
Vol 87 (9) ◽  
Author(s):  
M. Hori ◽  
J. Eades ◽  
R. S. Hayano ◽  
T. Ishikawa ◽  
J. Sakaguchi ◽  
...  

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