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小池 武志*; 長谷川 勝一; 早川 修平*; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 田村 裕和; et al.
AIP Conference Proceedings 2130, p.020011_1 - 020011_9, 2019/07
被引用回数:1 パーセンタイル:53.97Experimental results from the J-PARC E13 experiments are summarized. A new experimental set up of E13 has established a platform for the future -ray hypernuclear spectroscopy at J-PARC using kaon beams. New
rays are identified in
He and
F. The energy of 1.406 MeV for the
He
transition confirmed a sizable effect of Charge Symmetry Breaking (CSB) in
interaction in the
hypernuclear system. The identification of four
rays in
F is made for the first time in
shell hypernuclei. Especially, energy spacing of the ground state doublet is found to be 315.5 keV. A good agreement with two theoretical calculations suggests that the theoretical formalism used in
shell hypernuclei is also applicable to heavier hypernuclei. Lastly, an overview of the future J-PARC E63 experiment is given.
柴田 崇統*; 高木 昭*; 池上 清*; 杉村 高志*; 南茂 今朝雄*; 内藤 富士雄*; 小林 仁*; 栗原 俊一*; 本田 洋介*; 佐藤 将春*; et al.
Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (インターネット), p.385 - 387, 2018/10
In order to satisfy the second term clinical trial condition of iBNCT, which requires 5 mA proton beam extraction from linac, beam operation of Lanthanum Hexaboride (LaB) filament has been started from Oct. 2017. In the test stand, plasma arc discharge properties and beam current measurement via Faraday-cup (FC) has been done under several ion source conditions. By Mar. 2018, 45 mA of beam current has been achieved at FC. Although the pulse width of arc discharge is limited to 200
s by the capacitor bank in arc pulser power supply, still the wave form of the arc discharge current/voltage and the resultant beam current at FC have shown very stable flat top (beam current fluctuation below 0.5 %) after 50
s. Further increase of beam current is required by optimization of AMFC (Axial Magnetic Field correction) field and filament emission which will be done in 2018.
Yang, S. B.*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; et al.
Physical Review Letters, 120(13), p.132505_1 - 132505_5, 2018/03
被引用回数:7 パーセンタイル:51.04(Physics, Multidisciplinary)We report on the first observation of rays emitted from an
-shell hypernucleus,
F. The energy spacing between the ground state doublet,
and
states, of
F is determined to be
keV by measuring the
-ray energy of the
transition. In addition, three
-ray peaks are observed and assigned as
,
, and
transitions. The excitation energies of the
and
states are determined to be
keV and
keV, respectively. It is found that the ground state doublet spacing is well described by theoretical models based on existing
- and
-shell hypernuclear data.
田村 裕和*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; Hwang, S.; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; et al.
JPS Conference Proceedings (Internet), 17, p.011004_1 - 011004_11, 2017/07
The present status and future prospects of precision -ray spectroscopy of
hypernuclei are described. A new experiment (J-PARC E13) has been performed at the J-PARC K1.8 line employing a newly-developed germanium (Ge) detector array, Hyperball-J, via the
reaction on
He and
F targets. This is the first study of
-shell and
-shell
hypernuclei with Ge detectors. The
He target spectrum exhibited a
-ray peak of
at
MeV. Compared with the energy (
MeV) of the corresponding transition for the mirror hypernucleus,
, the present result clearly indicates a large charge symmetry breaking (CSB) effect. This decisive data for CSB allows a stringent test of baryon-baryon interaction models. As for the
F target run, a preliminary spectrum shows several
-ray peaks assigned to
transitions. Future plans of
-ray spectroscopy are also discussed.
中川 真菜美*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; Hwang, S.; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; et al.
JPS Conference Proceedings (Internet), 17, p.012009_1 - 012009_4, 2017/07
One of the main items of the J-PARC E13 experiment is the search for excited states of the He hypernucleus via the
He
reaction at 1.5 GeV/c. The missing-mass spectrum of the
He
reaction was obtained in an angular range from 0 to 20 degrees. We show the count-base spectrum of the missing-mass in the angular range from 2 to 14 degrees. The ground state of
He and
He were clearly observed in the missing-mass spectrum. We also show three missing-mass spectra divided by the reaction angle.
三輪 浩司*; 長谷川 勝一; 早川 修平; 細見 健二; 今井 憲一; 近藤 恭弘; 成木 恵; 佐甲 博之; 佐藤 進; 杉村 仁志; et al.
JPS Conference Proceedings (Internet), 17, p.041002_1 - 041002_6, 2017/07
In order to test theoretical frameworks of the Baryon-Baryon () interactions and to confirm the "Pauli effect between quarks" for the first time, we have proposed an experiment (J-PARC E40) to measure low-energy hyperon-proton scattering cross sections of the
,
elastic scatterings and the
inelastic scattering in the momentum range of
in the laboratory system. Experimentally, we detect two successive reactions of the
production
and the
scattering (
) in the same liquid hydrogen target. The former is measured with two magnetic spectrometers, and the latter with a scattered proton detector (CATCH). By using a high intensity
beam, we estimate that more than 10000 scattering events can be identified. In this experiment, we aim to provide good quality scattering data to test the theoretical models of the
interaction.
Yang, S. B.*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; Hwang, S.; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; et al.
JPS Conference Proceedings (Internet), 17, p.012004_1 - 012004_4, 2017/07
The first -ray spectroscopy of
-shell hypernucleus,
F, is performed in June, 2015 at the J-PARC K1.8 beam line (J-PARC E13). Precise energy levels of
F can be revealed by measured
rays in this experiment. Especially, the strength of
spin-spin interaction in
-shell hypernucleus is obtained through the energy spacing of the ground-state doublet of the hypernucleus. By comparing its strength between the
,
, and
-shell hypernuclei, a radial dependence
interaction is investigated. The hypernucleus is produced through the
reaction with the beam momentum of 1.8 GeV/c. In very preliminary results, we observed two
rays, and their energies are
keV and
keV where the uncertainties are only statistical.
本多 良太郎*; 長谷川 勝一; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 永宮 正治; 佐甲 博之; 佐藤 進; 杉村 仁志; et al.
Physical Review C, 96(1), p.014005_1 - 014005_23, 2017/07
被引用回数:13 パーセンタイル:75.45(Physics, Nuclear)We searched for the bound state of the neutron-rich -hypernucleus
H, using the
Li
double charge-exchange reaction at a
beam momentum of 1.2 GeV/
at J-PARC. A total of
was driven onto a
Li target of 3.5 g/cm
thickness. No event was observed below the bound threshold, i.e., the mass of
H+
, in the missing-mass spectrum of the
Li
reaction in the
angular range. Furthermore, no event was found up to 2.8 MeV/c
above the bound threshold.
永江 知文*; 江川 弘行; 長谷川 勝一; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; et al.
Proceedings of Science (Internet), 7 Pages, 2017/05
We have carried out a pilot data taking of the J-PARC E05 experiment to search for the bound state peaks of Be in the
C
reaction at 1.8 GeV/
. The measurement was performed at the K1.8 beam line of the J-PARC hadron experimental hall with a typical
beam intensity of
every six seconds. So far the best energy resolution of about 6 MeV FWHM was achieved with the existing SKS spectrometer. With a reasonable statistics, we have succeeded to observe peak structures in the bound region, which seems to suggest that the potential depth of
would be deeper than 14 MeV estimated in the previous measurements.
市川 裕大; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 今井 憲一; 金原 慎二; 中田 祥之; 佐甲 博之; 佐藤 進; et al.
JPS Conference Proceedings (Internet), 13, p.020007_1 - 020007_5, 2017/02
これまで反K中間子と原子核の間の相互作用はK中間子原子(K-中間子と原子核の電磁相互作用による束縛状態)のX線を用いて研究が行われてきた。しかし、このK中間子原子のX線測定では理論モデルの種類によって結果が大きく依存するという問題がため、X線測定だけでは相互作用を決定することが困難である。そこで、われわれはC(K
, p)反応におけるエネルギースペクトルを測定し、理論計算と比較する手法を用いて反K中間子と原子核の間の相互作用を決定しようとしている。この手法は既にKEK E548実験で行われているが、実験セットアップ上の問題点が指摘されているため、過去の高エネルギー加速器研究機構での実験では不十分である。そこで、われわれはJ-PARCにおいて再実験を行い、正しく
C(K
, p)のスペクトルを取得することに成功した。
佐甲 博之; 原田 寛之; 坂口 貴男*; 中條 達也*; 江角 晋一*; 郡司 卓*; 長谷川 勝一; Hwang, S.; 市川 裕大; 今井 憲一; et al.
Nuclear Physics A, 956, p.850 - 853, 2016/12
被引用回数:11 パーセンタイル:66.25(Physics, Nuclear)We are designing a large acceptance heavy-ion spectrometer at J-PARC based on a Toroidal magnet to measure hadrons, lepton pairs, and event-by-event fluctuations. We are also designing a closed geometry spectrometer to measure hypernuclei to study weak decays and magnetic moments. In this presentation, the preliminary version of the designed acceleration scheme, as well as the spectrometers and their expected performance and physics results are presented.
栗原 俊一*; 小林 仁*; 杉村 高志*; 平野 耕一郎
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (インターネット), p.814 - 816, 2016/11
照射損傷は加速器の構成要素の各部分に観察される問題である。加速管,スクレーパー,モニター、そして標的と特に陽子加速器,イオン加速器では憂慮される問題である。われわれは、実際の加速器でのその場観察を究極の目標として、加速器で使用される様々な物質の照射損傷、特にブリスタリングの観察を続け、光源としてレーザーを用い、その反射光からの情報により遠方で加速器の動作中のその場観察を行える方法を検討した。観察により得たブリスタリングの生成過程とともに、この観察方法の原理、ならびに適用限界を報告する。
山本 剛史*; 長谷川 勝一; 早川 修平; 細見 健二; Hwang, S.; 市川 裕大; 今井 憲一; 金原 慎二; 中田 祥之; 佐甲 博之; et al.
Physical Review Letters, 115(22), p.222501_1 - 222501_5, 2015/11
被引用回数:64 パーセンタイル:93.12(Physics, Multidisciplinary)The energy spacing between the spin-doublet bound state of He
was determined to be
keV, by measuring
rays for the
transition with a high efficiency germanium detector array in coincidence with the
He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus
H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in
interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the
ground state but is vanishingly small in the
excited state, demonstrating that the
CSB interaction has spin dependence.
市川 裕大; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; et al.
JPS Conference Proceedings (Internet), 8, p.021020_1 - 021020_7, 2015/09
反応を用いて最も単純なK中間子原子核
を探索する実験を行った。そして、世界で初めて本反応において
粒子の生成領域から
(1405)/
(1385)粒子の生成領域までと広い質量領域での二重微分断面積を測定した。
や
粒子の生成領域においては2.13GeV/
付近に観測した
カスプ起因のピーク以外おおむね準自由過程をもとにしたシミュレーションと実験結果が一致することを確認した。一方で、
の生成領域ではシミュレーションと比べて実験データのピーク位置が-24MeV/
ずれていることを観測した。
高橋 智則*; 江川 弘行; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; et al.
JPS Conference Proceedings (Internet), 8, p.022011_1 - 022011_6, 2015/09
A search for the pentaquark in the
reaction was performed at the J-PARC Hadron Facility. Two data samples were collected in 2010 and 2012 at
beam momenta of 1.92 and 2.0 GeV/
, respectively. No peak structure was observed in the missing mass spectra obtained from either data set. The upper limit for the production cross section averaged over the scattering-angle range of
to
in the laboratory frame was found to be 0.28
b/sr. The decay width of the
can be directly connected to the production cross section through a theoretical calculation using an effective Lagrangian. The estimated upper limits of the width were 0.41 and 2.8 MeV for the spin-parities of
and
, respectively.
山本 剛史*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; et al.
JPS Conference Proceedings (Internet), 8, p.021017_1 - 021017_6, 2015/09
A -ray spectroscopy experiment via the
reaction (J-PARC E13-1st) will be performed at the J-PARC Hadron Experimental Facility using a newly developed Ge detector array, Hyperball-J. Spin-dependent
interactions will be studied through the precise measurement of the structure of hypernuclei,
He and
F. In May 2013, commissioning of whole detector system was carried out and calibration data were taken. In particular, production cross sections of
and
C via the
reaction on the CH
target for
and 1.8 GeV/
were obtained.
佐々木 侑輝*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; et al.
JPS Conference Proceedings (Internet), 8, p.022013_1 - 022013_4, 2015/09
A hypernuclear -ray spectroscopy experiment (E13) will be performed using
beam at the K1.8 beam line of the J-PARC Hadron Experimental Facility in 2015. In this experiment, we will determine the
value of the
spin-flip transition of the ground state doublet in
to investigate the magnetic moment of a
hyperon in nuclei. In order to check the performance of the whole spectrometer system of E13, a commissioning run was performed at the K1.8 beam line in 2013. We confirmed that the E13 setup is almost ready for the next beam time in 2015. In particular, new detectors for suppressing events from the two main
decay modes in the on-line and off-line analyses are installed. As a result, the signal to noise ratio of
spectra is drastically improved, and the sensitivity to the
measurement is expected to increase.
Han, Y.*; 長谷川 勝一; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; J-PARC E42 Collaboration*; 他23名*
JPS Conference Proceedings (Internet), 8, p.021002_1 - 021002_5, 2015/09
The famed yet elusive H-dibaryon, an exotic quark state (), was predicted several decades ago and also supported by recent Lattice QCD calculations. The E42 experiment has been approved at J-PARC to search for the H-dibaryon with high statistics. A large acceptance hyperon spectrometer with a time projection chamber (TPC) will be used for searching the H-dibaryon from
reaction off nuclei via its possible following decays such as
. The E42 experiment has high sensitivity both above and below
threshold and will be the definitive experiment on the existence of the H-dibaryon, once and for all. Recent progress and achievements of the E42 collaboration will be presented, which include simulations on estimation of TPC performance in the electric field and the magnetic field, testing and optimization of a prototype TPC, and preparation of various detectors.
Lee, J. Y.*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; et al.
JPS Conference Proceedings (Internet), 8, p.021008_1 - 021008_6, 2015/09
A new single-sided silicon micro-strip detector (SSD) is being developed at the J-PARC K1.8 beam line for an emulsion-counter hybrid experiment (J-PARC E07). The SSD will be mainly used for vertex measurements in emulsion plates. Two prototypes of SSD have been fabricated to check the performance of the circuit board and silicon sensors. The first prototype consists of only one layer of a silicon sensor whereas the second prototype consists of two layers of silicon sensors. The final product will be a stack of 4 layers of silicon sensors in the order of -
-
-
. The first and second prototypes of SSD have been tested and the final product will be fabricated based on the test result.
佐甲 博之; Hwang, S.; 市川 裕大; 今井 憲一; 佐藤 進; 杉村 仁志
Proceedings of Science (Internet), 4 Pages, 2015/05
J-PARC E42実験において、H-ダイバリオン探索のためのGEM(ガス電子増幅器)を用いたTPC(Time Projection Chamber)を開発している。このTPCを設計するため、小型TPC試験機を製作しテスト実験を行い、性能評価を行った。放射線源を用いてGEMの長期計測テストを行い、E42と同等の期間での計測に成功した。大阪大学RCNPにおける陽子ビームを用いた実験では、イオンバックフローによる飛跡位置の歪みを0.2mm以下に抑えることに成功した。