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Hori M, Aghai-Khozani H, Sótér A, Dax A, Barna D. Laser Spectroscopy Measurements of Metastable Pionic Helium Atoms at Paul Scherrer Institute. FEW-BODY SYSTEMS 2021; 62:63. [PMID: 34720287 PMCID: PMC8550253 DOI: 10.1007/s00601-021-01630-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
We 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.
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Affiliation(s)
- M. Hori
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
| | - H. Aghai-Khozani
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
- Present Address: McKinsey and Company, Munich, Germany
| | - A. Sótér
- Present Address: ETH Zürich, IPA, Zurich, Switzerland
| | - A. Dax
- Present Address: Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - D. Barna
- CERN, CH-1211 Geneva, Switzerland
- Present Address: Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Budapest, Hungary
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Hori M. Recent progress of laser spectroscopy experiments on antiprotonic helium. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:20170270. [PMID: 29459410 PMCID: PMC5829173 DOI: 10.1098/rsta.2017.0270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/02/2018] [Indexed: 06/08/2023]
Abstract
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 109 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 8×10-10 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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Affiliation(s)
- Masaki Hori
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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Hori M. Precision laser spectroscopy experiments on antiprotonic helium. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201818101001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
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.
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Tanaka S, Nakaya Y, Narikawa R, Ninomiya K, Onishi J, Pearson M, Openshaw R, Saiba S, Tanuma R, Totsuka Y, Murata J. Search of non-standard strong gravity at nuclear scale using electron spin geodetic precession. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146605021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sótér A, Todoroki K, Kobayashi T, Barna D, Horváth D, Hori M. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:023302. [PMID: 24593349 DOI: 10.1063/1.4863648] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The Atomic Spectroscopy and Collisions Using Slow Antiprotons experiment at the Antiproton Decelerator (AD) facility of CERN constructed segmented scintillators to detect and track the charged pions which emerge from antiproton annihilations in a future superconducting radiofrequency Paul trap for antiprotons. A system of 541 cast and extruded scintillator bars were arranged in 11 detector modules which provided a spatial resolution of 17 mm. Green wavelength-shifting fibers were embedded in the scintillators, and read out by silicon photomultipliers which had a sensitive area of 1 × 1 mm(2). The photoelectron yields of various scintillator configurations were measured using a negative pion beam of momentum p ≈ 1 GeV/c. Various fibers and silicon photomultipliers, fiber end terminations, and couplings between the fibers and scintillators were compared. The detectors were also tested using the antiproton beam of the AD. Nonlinear effects due to the saturation of the silicon photomultiplier were seen at high annihilation rates of the antiprotons.
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Affiliation(s)
- A Sótér
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
| | - K Todoroki
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - T Kobayashi
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - D Barna
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - D Horváth
- Wigner Research Center of Physics, H-1525 Budapest, Hungary
| | - M Hori
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
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Aghai-Khozani H, Barna D, Corradini M, Hayano R, Hori M, Kobayashi T, Leali M, Lodi-Rizzini E, Mascagna V, Prest M, Soter A, Todoroki K, Vallazza E, Venturelli L, Zurlo N. Experimental results on antiproton–nuclei annihilation cross section at very low energies. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146609001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Sótér A, Hori M, Barna D, Hayano R, Dax A, Friedreich S, Juhász B, Pask T, Widmann E, Horváth D, Venturelli L, Zurlo N. Antiproton–to–electron mass ratio determined by two-photon laser spectroscopy of antiprotonic helium atoms. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146605020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hori M, Sótér A, Dax A. Development of narrowband lasers for spectroscopy of antiprotonic atoms. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146605006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Todoroki K, Hori M, Aghai-Khozani H, Barna D, Corradini M, Kobayashi T, Leali M, Lodi-Rizzini E, Mascagna V, Prest M, Soter A, Vallazza E, Venturelli L, Zurlo N, Hayano R. Beam Diagnostics for Measurements of Antiproton Annihilation Cross Sections at Ultra-low Energy. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146609020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Two-photon laser spectroscopy of antiprotonic helium and the antiproton-to-electron mass ratio. Nature 2011; 475:484-8. [PMID: 21796208 DOI: 10.1038/nature10260] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 05/26/2011] [Indexed: 12/13/2022]
Abstract
Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic helium (pHe(+)) is a three-body atom consisting of a normal helium nucleus, an electron in its ground state and an antiproton (p) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively n and l, such that n ≈ l + 1 ≈ 38. These atoms are amenable to precision laser spectroscopy, the results of which can in principle be used to determine the antiproton-to-electron mass ratio and to constrain the equality between the antiproton and proton charges and masses. Here we report two-photon spectroscopy of antiprotonic helium, in which p(3)He(+) and p(4)He(+) isotopes are irradiated by two counter-propagating laser beams. This excites nonlinear, two-photon transitions of the antiproton of the type (n, l) → (n - 2, l - 2) at deep-ultraviolet wavelengths (λ = 139.8, 193.0 and 197.0 nm), which partly cancel the Doppler broadening of the laser resonance caused by the thermal motion of the atoms. The resulting narrow spectral lines allowed us to measure three transition frequencies with fractional precisions of 2.3-5 parts in 10(9). By comparing the results with three-body quantum electrodynamics calculations, we derived an antiproton-to-electron mass ratio of 1,836.1526736(23), where the parenthetical error represents one standard deviation. This agrees with the proton-to-electron value known to a similar precision.
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Hayano RS. Spectroscopy of antiprotonic helium atoms and its contribution to the fundamental physical constants. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2010; 86:1-10. [PMID: 20075605 PMCID: PMC3417566 DOI: 10.2183/pjab.86.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 11/17/2009] [Indexed: 05/28/2023]
Abstract
Antiprotonic helium atom, a metastable neutral system consisting of an antiproton, an electron and a helium nucleus, was serendipitously discovered, and has been studied at CERN's antiproton decelerator facility. Its transition frequencies have recently been measured to nine digits of precision by laser spectroscopy. By comparing these experimental results with three-body QED calculations, the antiproton-to-electron massratio was determined as 1836.152674(5). This result contributed to the CODATA recommended values of the fundamental physical constants
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Affiliation(s)
- Ryugo S Hayano
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyoku,Tokyo, Japan.
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Hori M, Hayano RS, Fukuta M, Koyama T, Nobusue H, Tanaka J. Large-area imager of hydrogen leaks in fuel cells using laser-induced breakdown spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2009; 80:103104. [PMID: 19895051 DOI: 10.1063/1.3244089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We constructed a simple device, which utilized laser-induced breakdown spectroscopy to image H2 gas leaking from the surfaces of hydrogen fuel cells to ambient air. Nanosecond laser pulses of wavelength lambda=532 nm emitted from a neodymium-doped yttrium aluminum garnet laser were first compressed to a pulse length Deltat<1 ns using a stimulated Brillouin backscattering cell. Relay-imaging optics then focused this beam onto the H(2) leak and initiated the breakdown plasma. The Balmer-alpha (H-alpha) emission that emerged from this was collected with a 2-m-long macrolens assembly with a 90-mm-diameter image area, which covered a solid angle of approximately 1 x 10(-3)pi steradians seen from the plasma. The H-alpha light was isolated by two 100-mm-diameter interference filters with a 2 nm bandpass, and imaged by a thermoelectrically cooled charge-coupled device camera. By scanning the position of the laser focus, the spatial distribution of H2 gas over a 90-mm-diameter area was photographed with a spatial resolution of < or = 5 mm. Photoionization of the water vapor in the air caused a strong H-alpha background. By using pure N2 as a buffer gas, H2 leaks with rates of <1 cc/min were imaged. We also studied the possibilities of detecting He, Ne, or Xe gas leaks.
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Affiliation(s)
- M Hori
- Max-Planck Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
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Testing CPT invariance with antiprotonic atoms. Radiat Phys Chem Oxf Engl 1993 2007. [DOI: 10.1016/j.radphyschem.2006.01.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hori M, Dax A, Eades J, Gomikawa K, Hayano RS, Ono N, Pirkl W, Widmann E, Torii HA, Juhász B, Barna D, Horváth D. Determination of the antiproton-to-electron mass ratio by precision laser spectroscopy of pHe+. PHYSICAL REVIEW LETTERS 2006; 96:243401. [PMID: 16907239 DOI: 10.1103/physrevlett.96.243401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Indexed: 05/11/2023]
Abstract
A femtosecond optical frequency comb and continuous-wave pulse-amplified laser were used to measure 12 transition frequencies of antiprotonic helium to fractional precisions of (9-16)x10(-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 Mp/me=1836.152674(5).
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Affiliation(s)
- M Hori
- CERN, CH-1211 Geneva 23, Switzerland
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Hori M, Eades J, Hayano RS, Pirkl W, Widmann E, Yamaguchi H, Torii HA, Juhász B, Horváth D, Suzuki K, Yamazaki T. Observation of cold, long-lived antiprotonic helium ions. PHYSICAL REVIEW LETTERS 2005; 94:063401. [PMID: 15783728 DOI: 10.1103/physrevlett.94.063401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2004] [Indexed: 05/24/2023]
Abstract
Cold, two-body antiprotonic helium ions p 4He2+ and p 3He2+ with 100-ns-scale lifetimes, occupying circular states with the quantum numbers ni=28-32 and li=ni-1 have been observed. They were produced by cooling three-body antiprotonic helium atoms in an ultra-low-density helium target at temperature T approximately 10 K by atomic collisions, and then removing their electrons by inducing a laser transition to an autoionizing state. The lifetimes of p 3He2+ against annihilation induced by collisions were shorter than those of p 4He2+, and decreased for larger-ni states.
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Affiliation(s)
- M Hori
- CERN, CH-1211 Geneva 23, Switzerland
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Kuroda N, Torii HA, Franzen KY, Wang Z, Yoneda S, Inoue M, Hori M, Juhász B, Horváth D, Higaki H, Mohri A, Eades J, Komaki K, Yamazaki Y. Confinement of a large number of antiprotons and production of an ultraslow antiproton beam. PHYSICAL REVIEW LETTERS 2005; 94:023401. [PMID: 15698175 DOI: 10.1103/physrevlett.94.023401] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2003] [Indexed: 05/24/2023]
Abstract
We have used a radio frequency quadrupole decelerator to decelerate antiprotons emerging from the CERN Antiproton Decelerator from MeV- to keV-scale energy, and collected five decelerated pulses in a multiring trap. Some 5 x 10(6) antiprotons were stacked in this way. Cooling of the trapped antiprotons by a simultaneously trapped electron plasma was studied nondestructively via shifts in plasma mode frequencies. We have also demonstrated the first step in extracting a 10-500 eV antiproton beam from the trap.
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Affiliation(s)
- N Kuroda
- Institute of Physics, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
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Hori M, Hayano RS, Widmann E, Torii HA. Resolution enhancement of pHe+ atomic line profiles measured with a pulsed dye laser and a Fizeau wavelength meter. OPTICS LETTERS 2003; 28:2479-2481. [PMID: 14690120 DOI: 10.1364/ol.28.002479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A Fizeau wavelength meter was used to compensate for fluctuations in the longitudinal mode structure and wavelength of a pulsed dye laser. The average laser linewidth was effectively narrowed by selection of laser pulses with a single longitudinal mode. These techniques were recently employed to measure some atomic transition wavelengths in pHe+ to fractional precisions greater than 1 part in 10(7). The wavelengths were absolutely calibrated against iodine or tellurium lines by absorption spectroscopy or against neon or argon lines by optogalvanic spectroscopy.
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