Profile Information
- Affiliation
- Professor, Institute of Space and Astronautical Science, Japan Aerospace Exploration AgencyProfessor, School of Physical Sciences, The Graduate University for Advanced StudiesVisiting Professor, Graduate School of Science and Engineering, Aoyama Gakuin University
- Degree
- Doctor of Science(Feb, 1991, The University of Tokyo)
- J-GLOBAL ID
- 200901011121067404
- researchmap Member ID
- 1000013960
「初期宇宙の素粒子的描像での理解」を目指して低エネルギー反粒子宇宙線観測気球実験に参画。2006年からは自ら気球実験を実施してきた経験をベースに,日本で唯一気球実験を運営しているJAXA宇宙科学研究所の教授に着任し,大気球実験の実施責任者として大学の研究者等による宇宙科学研究を推進している。大気球,観測ロケットといった小型飛翔体による科学成果の創出に加えて宇宙科学研究を場とした幅広い人材育成への貢献にも取り組んでいる。
Major Research Interests
25Research Areas
2Research History
7-
Oct, 1996 - Mar, 1997
Education
2-
Apr, 1985 - Feb, 1991
-
Apr, 1981 - Mar, 1985
Committee Memberships
7-
Feb, 2013 - Jan, 2015
Awards
1Major Papers
213-
Physical Review Letters, 132(13), Mar 25, 2024 Peer-reviewed
-
Physical Review Letters, 108(13) 131301, Mar, 2012 Peer-reviewedIn two long-duration balloon flights over Antarctica, the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) collaboration has searched for antihelium in the cosmic radiation with the highest sensitivity reported. BESS-Polar I flew in 2004, observing for 8.5 days. BESS-Polar II flew in 2007-2008, observing for 24.5 days. No antihelium candidate was found in BESS-Polar I data among 8.4 x 10(6) vertical bar Z vertical bar = 2 nuclei from 1.0 to 20 GV or in BESS-Polar II data among 4: 0 x 10(7) vertical bar Z vertical bar = 2 nuclei from 1.0 to 14 GV. Assuming antihelium to have the same spectral shape as helium, a 95% confidence upper limit to the possible abundance of antihelium relative to helium of 6.9 x 10(-8) was determined combining all BESS data, including the two BESS-Polar flights. With no assumed antihelium spectrum and a weighted average of the lowest antihelium efficiencies for each flight, an upper limit of 1.0 x 10(-7) from 1.6 to 14 GV was determined for the combined BESS-Polar data. Under both antihelium spectral assumptions, these are the lowest limits obtained to date.
-
Physical Review Letters, 108(5) 51102, Jan, 2012 Peer-reviewedThe energy spectrum of cosmic-ray antiprotons ((p) over bar 's) from 0.17 to 3.5 GeV has been measured using 7886 (p) over bar 's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary (p) over bar calculations. Cosmologically primary (p) over bar 's have been investigated by comparing measured and calculated (p) over bar spectra. BESS-Polar II data show no evidence of primary (p) over bar 's from the evaporation of primordial black holes.
-
Astroparticle Physics, 28(1) 154-167, Sep, 2007 Peer-reviewedWe measured low energy cosmic-ray proton and helium spectra in the kinetic energy range 0.215-21.5 GeV/n at different solar activities during a period from 1997 to 2002. The observations were carried out with the BESS spectrometer launched on a balloon at Lynn Lake, Canada. A calculation for the correction of secondary particle backgrounds from the overlying atmosphere was improved by using the measured spectra at small atmospheric depths ranging from 5 through 37 g/cm(2). The uncertainties including statistical and systematic errors of the obtained spectra at the top of atmosphere are 5-7% for protons and 6-9% for helium nuclei in the energy range 0.5-5 GeV/n. (C) 2007 Elsevier B.V. All rights reserved.
-
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 645(5-6) 472-475, Feb, 2007 Peer-reviewed
-
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 632(4) 475-479, Jan, 2006 Peer-reviewedWe measured atmospheric antiproton spectra in the energy range 0.2 to 3.4 GeV, at sea level and at balloon altitude in the atmospheric depth range 4.5 to 26 g/cm(2). The observed energy spectra, including our previous measurements at mountain altitude, were compared with estimated spectra calculated on various assumptions regarding the energy distribution of antiprotons that interacted with air nuclei. (c) 2005 Elsevier B.V. All rights reserved.
-
Physical Review Letters, 95(8) 81101, Aug, 2005 Peer-reviewedWe performed a search for cosmic-ray antideuterons using data collected during four BESS balloon flights from 1997 to 2000. No candidate was found. We derived, for the first time, an upper limit of 1.9x10(-4) (m(2)s sr GeV/nucleon)(-1) for the differential flux of cosmic-ray antideuterons, at the 95% confidence level, between 0.17 and 1.15 GeV/nucleon at the top of the atmosphere.
-
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 594(1-2) 35-46, Jul, 2004 Peer-reviewedPrimary and atmospheric cosmic-ray spectra were precisely measured with the BESS-TeV spectrometer. The spectrometer was upgraded from BESS-98 to achieve seven times higher resolution in momentum measurement. We report absolute fluxes of primary protons and helium nuclei in the energy ranges, 1-540 GeV and 1-250 GeV/n, respectively, and absolute flux of atmospheric muons in the momentum range 0.6-400 GeV/c. (C) 2004 Elsevier B.V. All rights reserved.
-
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 581(3-4) 272-273, Feb, 2004
-
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 577(1-2) 10-17, Dec, 2003 Peer-reviewedEnergy spectra of atmospheric secondary cosmic-ray protons and antiprotons were measured at mountain altitude, 2770 m above sea level. We observed more than 10(5) protons and 10(2) antiprotons. Our proton spectrum is generally consistent with other previous measurements. The observed antiproton spectrum suggests that the energy loss due to non-annihilation processes is less significant than that assumed in previous model calculations. (C) 2003 Published by Elsevier B.V.
-
PHYSICAL REVIEW LETTERS, 88(5) 51101, Feb, 2002 Peer-reviewedThe energy spectra of cosmic-ray low-energy antiprotons ((p) over bar 's) and protons (p's) have been measured by BESS in 1999 and 2000, during a period covering reversal at the solar magnetic field. Based an these measurements, a sudden increase of the (p) over bar /p flux ratio following the solar magnetic field reversal was observed, and it generally agrees with a drift model of the solar modulation.
-
PHYSICAL REVIEW LETTERS, 81(19) 4052-4055, Nov, 1998 Peer-reviewedThe absolute fluxes of the cosmic-ray antiprotons at solar minimum are measured in the energy range 0.18 to 1.4 GeV, based on 43 events unambiguously detected in BESS 1995 data. The resultant energy spectrum appears to be flat below 1 GeV, compatible with a possible admixture of primary antiproton component with a soft energy spectrum, while the possibility of secondary antiprotons alone explaining the data cannot be excluded with the present accuracy. Further improvement of statistical accuracy and extension of the energy range are planned in future BESS flights. [S0031-9007(98)07573-5].
-
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 422(1-4) 319-324, Mar, 1998 Peer-reviewedA very sensitive search for cosmic-ray antihelium was performed using data obtained from three scientific flights of the BESS magnetic rigidity spectrometer. We have not observed any antihelium; this places a model-independent upper limit (95% C.L.) on the antihelium flux of 6 x 10(-4) m(-2)sr(-1)s(-1) at the top of the atmosphere in the rigidity region 1 to 16 GV, after correcting for the estimated interaction loss of antihelium in the air and in the instrument. The corresponding upper limit on the <(He)over bar>/He flux ratio is 3.1 x 10(-6), 30 times more stringent than the limits obtained in similar rigidity regions with magnetic spectrometers previous to BESS. (C) 1998 Published by Elsevier Science B.V.
-
Physical Review Letters, 75(21) 3792-3795, Nov, 1995 Peer-reviewedA search for cosmic-ray antiprotons was performed using a balloon-borne experiment with a superconducting magnetic rigidity spectrometer (BESS). We have detected four antiprotons in the kinetic energy range between 300 and 500 MeV, the first antiprotons to be identified by a direct mass measurement. The corresponding (p) over bar/p flux ratio at the top of the atmosphere is found to be 1.2(-0.65)(+1.0) X 10(-5). No antiprotons were observed in the range between 175 and 300 MeV, resulting in a 90% C.L. upper limit on the flux ratio of 2.9 X 10(-5).
-
Physics Letters B, 248(1-2) 211-219, Sep 27, 1990 Peer-reviewedA search has been performed for the production of neutralinos (χ, χ′) in e+e- annihilation at energies near the Z0 pole. No evidence for these particles was found either in searches for events with two acoplanar jets, low visible energy, and missing pt (sensitive to Z0→χχ′→χχff) or in searches for single-photon events (sensitive to Z0→χχ′→χχγ). Model independent upper limits (at the 95% CL) on the branching ratio for the decay mode Z0 →χχ′ of a few 10-4 are obtained for most of the range of neutralino masses that is kinematically accessible at LEP energies. Upper limits on the mixing factor of neutralinos are also placed as a function of the neutralino masses. © 1990.
-
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 242(2) 299-308, Jun, 1990 Peer-reviewed
Misc.
111-
大気球シンポジウム: 2022年度 = Balloon Symposium: 2022, Nov, 2022大気球シンポジウム 2022年度(2022年11月7-8日. ハイブリッド開催(JAXA相模原キャンパス& オンライン)) Balloon Symposium 2022 (November 7-8, 2022. Hybrid(in-person & online) Conference (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan 著者人数: 26名 資料番号: SA6000177012 レポート番号: isas22-sbs-012
-
宇宙航空研究開発機構宇宙科学研究所大気球シンポジウム (2021年度), isas21-sbs-032, Nov 2, 2021
Books and Other Publications
4-
"Neutrino Oscillation and their Origin", eds. Y.Suzuki, M.Nakahata, M.Miura and K.Kaneyuki, World Scientific., 2001
-
Neutrino Oscillation and their Origin", eds. Y.Suzuki, M.Nakahata, M.Miura and K.Kaneyuki, World Scientific., 2001
-
Proc. of 21st Intl. Symposium Space Technology and Science, 1998
-
Proc. of 21st Intl. Symposium Space Technology and Science, 1998
Presentations
24Teaching Experience
3-
最新物理講義 (青山学院大学理学部)
-
宇宙工学概論 (総合研究大学院大学物理科学研究科宇宙科学専攻)
-
宇宙システム工学特論I (総合研究大学院大学物理科学研究科宇宙科学専攻)
Professional Memberships
4Research Projects
16-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2014 - Mar, 2017
-
Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2010 - Mar, 2014
-
Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Jul, 2009 - Mar, 2014
-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, 2006 - 2009
-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, 2001 - 2005