Li, W.*; 山田 真也*; 橋本 直; 奥村 拓馬*; 早川 亮大*; 新田 清文*; 関澤 央輝*; 菅 大暉*; 宇留賀 朋哉*; 一戸 悠人*; et al.
Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02
希土類元素は放射性元素であるアクチノイドのアナログ元素としてしばしば利用される。セリウム(Ce)は希土類元素の中でも+3価と+4価の両方をとり得る特別な元素である。環境試料中のCeの+3価と+4価の比を調べる手段としてX線吸収端近傍構造(XANES)が有力であったが、チタン濃度が高いと蛍光X線の干渉のために測定ができないという問題があった。本研究では、L吸収端だけでなくL吸収端を調べ、さらに新しい検出器であるtransition-edge sensor (TES)を利用することでこれまでは測定が難しかった試料も測定可能にした。この結果は様々な環境試料に応用可能である。
相川 脩*; 橋本 直; 谷田 聖; 他73名*
Physics Letters B, 837, p.137637_1 - 137637_8, 2023/02
We measured a set of , , and invariant mass spectra below and above the mass threshold in -induced reactions on deuteron. We deduced the -wave and scattering amplitudes in the isospin 0 channel in the framework of a and coupled channel. We find that a resonance pole corresponding to is located at 1417.7(fitting errors)(systematic errors) + (fitting errors)(systematic errors)] MeV/, closer to the mass threshold than the value determined by the Particle Data Group.
橋本 直; 谷田 聖; 他68名*
Physical Review Letters, 128(11), p.112503_1 - 112503_6, 2022/03
We have measured the transition X-rays of kaonic He and He atoms using superconducting transition-edge-sensor microcalorimeters with an energy resolution better than 6 eV (FWHM). We determined the energies to be (stat) (syst) eV and (stat) (syst) eV, and widths to be (stat) (syst) eV and (stat) (stat) eV, for kaonic He and He, respectively. These values are nearly 10 times more precise than in previous measurements. Our results exclude the large strong-interaction shifts and widths that are suggested by a coupled-channel approach, and agree with calculations based on optical-potential models.
奥村 拓馬*; 東 俊行*; Bennet, D. A.*; Caradonna, P.*; Chiu, I. H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; 橋本 直; et al.
Physical Review Letters, 127(5), p.053001_1 - 053001_7, 2021/07
吉本 雅浩*; 藤田 真奈美; 橋本 直; 早川 修平; 市川 裕大; 市川 真也; 今井 憲一*; 七村 拓野; 成木 恵; 佐甲 博之; et al.
Progress of Theoretical and Experimental Physics (Internet), 2021(7), p.073D02_1 - 073D02_19, 2021/07
Bound-systems of - are studied via capture at rest followed by emission of a twin single- hypernucleus in the emulsion detectors. Two events forming extremely deep bound states were obtained by analysis of a hybrid method in the E07 experiment at J-PARC and reanalysis of the E373 experiment at KEK-PS. The decay mode of one event was assigned as +++. Since there are no excited states for daughter particles, the binding energy of the hyperon, , in nucleus was uniquely determined to be 6.27 0.27 MeV. Another - system via the decay + + brings a value, 8.00 0.77 MeV or 4.96 0.77 MeV, where the two possible values of correspond to the ground and the excited states of the daughter nucleus, respectively. Because the values are larger than those of the previously reported events (KISO and IBUKI), which are both interpreted as the nuclear state of the - system, these new events give the first indication of the nuclear state of the hypernucleus, .
早川 修平; 藤田 真奈美; 長谷川 勝一; 橋本 直; 細見 健二; 市川 裕大; 今井 憲一*; 七村 拓野; 成木 恵; 佐甲 博之; et al.
Physical Review Letters, 126(6), p.062501_1 - 062501_6, 2021/02
In an emulsion-counter hybrid experiment performed at J-PARC, a absorption event was observed which decayed into twin single- hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as NBe + He. For the binding energy of the hyperon in the -N system a value of MeV was deduced. The energy level of is likely a nuclear state which indicates a weak - coupling.
山我 拓巳*; 橋本 直; 谷田 聖; 他66名*
Physical Review C, 102(4), p.044002_1 - 044002_14, 2020/10
We have performed an exclusive measurement of the reaction at an incident kaon momentum of . In the invariant mass spectrum, a clear peak was observed below the mass threshold of , as a signal of the kaonic nuclear bound state, . The binding energy, decay width, and -wave Gaussian reaction form-factor of this state were observed to be , , and , respectively. The total production cross-section of , determined by its decay mode, was . We estimated the branching ratio of the state to the and decay modes as , by assuming that the physical processes leading to the final states are analogous to those of .
佐久間 史典*; 橋本 直; 谷田 聖; 他66名*
AIP Conference Proceedings 2249, p.020005_1 - 020005_10, 2020/07
The bound system, symbolically denoted as "", is the simplest -nuclear bound system which has been widely discussed as a consequence of the strongly attractive interaction in channels. Many theoretical works have pointed out the existence of the "" bound system, but the calculated properties such as the binding energy and the width spread out due to the uncertainty of the interaction below the mass threshold. Experimentally, there are several reports on observation of a "" candidate with the binding energy of around 100 MeV, however, no definitive evidence was available so far. At J-PARC, we conducted a experimental search for the "" bound system using He reaction at 1.0 GeV/ where the "" is expected to be directly produced via the reaction. We finally observed a bound state below the mass threshold in the final state, which can be interpreted as the "" bound state. The possible existence of the "" state is discussed from both aspects of production and decay.
佐久間 史典*; 橋本 直; 谷田 聖; 他66名*
JPS Conference Proceedings (Internet), 32, p.010088_1 - 010088_8, 2020/07
-nuclear bound states have been widely discussed as a consequence of the strongly attractive interaction in channels. Especially, the simplest -nuclear bound state of (denoted as "") has attracted the strong interest both of theoretical and experimental studies. We observed a bound state below the mass threshold with in-flight induced reactions on He target, which can be interpreted as the "" bound state. The possible existence of the "" state is discussed from both aspects of production and decay: "" and productions, and non-mesonic and mesonic decays, respectively.
山我 拓巳*; 橋本 直; 谷田 聖; 他66名*
JPS Conference Proceedings (Internet), 26, p.023008_1 - 023008_6, 2019/11
There is a long-standing argument of the existence of kaonic nucleus, which is a bound state of anti-kaon and nucleus. Theoretically, its existence is strongly supported, however its binding energy and width have not been established yet. It is strongly desired to have an experiment to investigate the simplest kaonic nucleus, so-called bound state. We performed an experiment to search for via the in-flight reaction at J-PARC. By studying invariant mass spectrum in the final state and its dependence on momentum transfer of , we observed a resonant state located below . The mass and width of this resonant state are MeV/, and MeV, respectively, which can be naturally interpreted as a theoretically predicted bound state.
川崎 新吾*; 橋本 直; 谷田 聖; 他72名*
JPS Conference Proceedings (Internet), 26, p.022009_1 - 022009_5, 2019/11
The spectral shape of the baryon was measured via the in-flight reaction at the J-PARC K1.8BR beam-line (J-PARC E31). The second E31 physics run was carried out in January and February, 2018. Approximately kaons were irradiated on the deuteron target. The missing mass spectrum for the where the residual final-state particles were and ("" spectrum) was measured for the first time.
浅野 秀光*; 橋本 直; 谷田 聖; 他72名*
AIP Conference Proceedings 2130, p.040018_1 - 040018_6, 2019/07
The structure of the hyperon is an important and long-standing issue related to the -nucleus interaction. The J-PARC E31 experiment has been performed to investigate the spectrum shape. Because it is hard to form the directly by a scattering in free space, E31 uses the reaction with an incident kaon momentum of 1 GeV/. We will identify three final states - , , so that the isospin structure of hyperon resonance states produced can be decomposed. The first physics run of the E31 experiment was performed in 2016. To enhance the statistics of the data set, we have performed the second physics run in the beginning of 2018. During the second run of E31, around kaons impacted on the deuteron target.
橋本 直; 谷田 聖; 他67名*
Physics Letters B, 789, p.620 - 625, 2019/02
における不変質量分布において、つまりが2つの陽子に束縛する質量閾値以下に顕著なピークを観測した。 = 350650MeV/という比較的大きな運動量移行領域を選ぶことで、準弾性散乱()に続いて残りの2各紙に吸収される反応()をはっきり分離することができる。観測したピークの単純なフィットによってBreit-Wignerポール位置 MeV、幅 MeV、そして波ガウス形状因子パラメータMeV/という値が""というストレンジネスを含む新しい原子核束縛システムについて得られた。
江川 弘行; 足利 沙希子; 長谷川 勝一; 橋本 直; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 金原 慎二*; 七村 拓野; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.021D02_1 - 021D02_11, 2019/02
A double- hypernucleus, , was observed by the J-PARC E07 collaborationin nuclear emulsions tagged by the reaction. This event was interpreted as a production and decay of ,, or via capture in .By assuming the capture in the atomic 3D state, the binding energy of two hyperons()of these double- hypernuclei are obtained to be, , and , respectively. Based on the kinematic fitting, is the most likely explanation for the observed event.
橋本 直; 谷田 聖; 他45名*
JPS Conference Proceedings (Internet), 17, p.072001_1 - 072001_4, 2017/07
We will measure kaonic helium X-rays using transition-edge-sensor microcalorimeters, TES, in the JPARC hadron experimental facility. To demonstrate the feasibility of the experiment, we performed a measurement of pionic carbon X-rays at PSI, where an excellent FWHM energy resolution of 7 eV at 6.4 keV was achieved. We also evaluated the expected TES performance in the kaon beam at J-PARC. The simulation results show that the TES spectrometer would work with a good energy resolution, and clear peaks of kaonic helium X-rays would be observed on a reasonably suppressed background.
井上 謙太郎*; 橋本 直; 谷田 聖; 他69名*
JPS Conference Proceedings (Internet), 17, p.072003_1 - 072003_4, 2017/07
We have taken the data of the reaction on the target in May, 2015. In this reaction, it is expected that the kicks a neutron and produces the in a backward angle. We identify the final state of by detecting the forward neutron, and and obtain the spectrum excluded and forward-going productions. We observed few hundred events in the region below the threshold.
橋本 直*; 谷田 聖; 他49名*
IEEE Transactions on Applied Superconductivity, 27(4), p.2100905_1 - 2100905_5, 2017/06
We are developing a new technique to apply transition-edge sensors (TESs) to X-ray spectroscopy of exotic atoms, especially of kaonic atoms. To demonstrate the feasibility of this pioneering project, performance of a TES-based X-ray detector was evaluated in pion- and kaon-beam environments at particle accelerators. We successfully observed X-rays from pionic-carbon atoms with a resolution as good as 7 eV FWHM at 6 keV. Also at a kaon beamline, we confirmed that the TES spectrometer will be able to achieve our resolution goal, 6 eV, in our first scientific campaign to measure X-rays from kaonic-helium atoms.
川崎 新吾*; 橋本 直*; 谷田 聖; 他59名*
JPS Conference Proceedings (Internet), 13, p.020018_1 - 020018_5, 2017/02
Experimental investigation of via the in-flight reaction is being performed at the J-PARC K1.8BR beam-line (J-PARC E31). The first E31 physics run was carried out in June, 2016. About kaons were irradiated on the deuteron target. The missing mass spectra of the "" reactions were measured. The difference between the two spectra was observed clearly, which tells us the existence of the interference term between the isospin = 0 and 1 amplitudes. The missing mass spectrum of the "" reaction was also measured, which gives the information on the =1 amplitude. The identification of the "" reaction seems successful.
原田 寛之; 明午 伸一郎; 白形 政司*; 佐藤 洋一*; 田村 文彦; 手島 昌己*; 橋本 義徳*; 五十嵐 進*; 小関 忠
JPS Conference Proceedings (Internet), 8, p.012010_1 - 012010_6, 2015/09
橋本 直*; 谷田 聖; J-PARC E15 Collaboration*; 他65名*
Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.061D01_1 - 061D01_11, 2015/06
An experiment to search for the bound state was performed via the in-flight reaction using kaons at 1 GeV/ at the J-PARC hadron experimental facility. In the semi-inclusive neutron missing-mass spectrum at , no significant peak was observed in the region corresponding to binding energy larger than 80 MeV, where a bump structure has been reported in the final state in different reactions. Assuming the state to be isotropically decaying into , mass-dependent upper limits on the production cross section were determined to be 30-180, 70-250, and 100-270 b/sr, for the natural widths of 20, 60, and 100 MeV, respectively, at 95% confidence level.