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論文

$$Xi^-$$ atomic X-ray spectroscopy using a counter-emulsion hybrid method

藤田 真奈美; 長谷川 勝一; 細見 健二; 市川 真也; 市川 裕大; Kim, S.; 七村 拓野; 佐甲 博之; 田村 裕和; 山本 剛史; et al.

Progress of Theoretical and Experimental Physics (Internet), 2022(12), p.123D01_1 - 123D01_17, 2022/12

https://doi.org/10.1093/ptep/ptac156
 被引用回数：0 パーセンタイル：0.01(Physics, Multidisciplinary)

$$Xi^-$$ atomic X-ray spectroscopy is one of the most useful methods for investigation of the $$Xi$$-nucleus strong interaction. Since the X-ray energy is shifted and/or broadened due to the $$Xi$$-nucleus strong interaction compared to those calculated from electromagnetic interaction alone, the measurement of the energy shift, $$Delta$$E, and the width, $$Gamma$$, give us information on the $$Xi$$-nucleus potential. A serious problem in the measurement is the significant background derived from in-flight $$Xi^-$$ decay. A novel method of identifying stopped $$Xi^-$$ events using the nuclear emulsion was developed to realize the first $$Xi^-$$ atomic X-ray spectroscopy experiment as the J-PARC E07 experiment, which also aimed at searching for $$LambdaLambda$$ and $$Xi^-$$ hypernuclei in the emulsion. The X-rays emitted from $$Xi^-$$ Br and $$Xi^-$$ Ag atoms were measured using germanium detectors. No clear peaks were observed in the obtained spectra. However, we succeeded in reducing the background to 1/170 by this method employing coincidence measurements using nuclear emulsion and X-ray detectors.

論文

Strangeness physics programs by S-2S at J-PARC

後神 利志*; 江端 健悟; 藤田 真奈美; 原田 健志; 長谷川 勝一; 細見 健二; 市川 裕大; 今井 憲一*; Kim, S.; 七村 拓野; et al.

EPJ Web of Conferences, 271, p.11002_1 - 11002_7, 2022/11

https://doi.org/10.1051/epjconf/202227111002

In the K1.8 beam-line at Hadron Experimental Facility of J-PARC, a new magnetic spectrometer S-2S is being installed. S-2S was designed to achieve a high momentum resolution of $$Delta p/p = 6 times 10^{-4}$$ in FWHM. Several strangeness-physics programs which require the high resolution will be realized by S-2S. The present article introduces J-PARC E70 (missing-mass spectroscopy of $$_{Xi}^{12}$$Be) and E94 (missing-mass spectroscopy of $$_{Lambda}^7$$Li, $$_{Lambda}^{10}$$B, and $$_{Lambda}^{12}$$C) experiments.

論文

Measurement of the differential cross sections of the $$Sigma^- p$$ elastic scattering in momentum range 470 to 850 MeV/$$c$$

三輪 浩司*; 藤田 真奈美; 長谷川 勝一; 細見 健二; 市川 裕大; 今井 憲一*; 七村 拓野; 成木 恵; 佐甲 博之; 佐藤 進; et al.

Physical Review C, 104(4), p.045204_1 - 045204_20, 2021/10

https://doi.org/10.1103/PhysRevC.104.045204
 被引用回数：13 パーセンタイル：89.06(Physics, Nuclear)

A high statistics $$Sigma p$$ scattering experiment is performed at the J-PARC Hadron Experimental Facility. Momentum-tagged $$Sigma^-$$s running in a liquid hydrogen target are accumulated by detecting the reaction with a high intensity $$pi^-$$ beam of 20 M/spill. The differential cross sections of the $$Sigma^- p$$ elastic scattering were derived with a drastically improved accuracy by identifying approximately 4,500 events from 1.72 $$times$$ 10$$^7$$ $$Sigma^-$$. The derived differential cross section shows a clear forward-peaking angular distribution for a $$Sigma^-$$ momentum range from 470 to 850 MeV/$$c$$. The accurate data will impose a strong constraint on the theoretical models of the baryon-baryon interactions.

論文

J-PARC E07; Systematic study of double strangeness system with hybrid emulsion method

吉田 純也; 赤石 貴也; 藤田 真奈美; 長谷川 勝一; 橋本 直; 細見 健二; 市川 真也; 市川 裕大; 今井 憲一*; Kim, S.; et al.

JPS Conference Proceedings (Internet), 33, p.011112_1 - 011112_8, 2021/03

https://doi.org/10.7566/JPSCP.33.011112

J-PARC E07 is the most ambitious and complex emulsion experiment to date investigating double hypernuclei with Hybrid emulsion method. The physics run at the K1.8 beam line in the J-PARC hadron experimental facility have been completed in 2017. The emulsion sheets are presently being analyzed with dedicated optical microscopes. Current statistics are estimated to be more 3 times than that of previous experiments. Quantitative data on the $$Lambda Lambda$$ and $$Xi N$$ interaction are being accumulated successfully via analysis of double $$Lambda$$ and $$Xi$$ hypernuclei. Multiple $$Xi$$ hypernucleus candidates suggests several features about $$Xi$$ hypernucleus that the identification efficiency of $$^{15}_Xi$$C is significantly higher than other mode, many daughters of $$^{15}_Xi$$C are identified as He or Be, and multiple bound states of $$Xi^-$$ exist in the $$^{14}$$N nucleus. An analysis of X-ray spectroscopy of $$Xi^-$$ hyperatoms are ongoing.

論文

Establishment of a modern experimental technique of a $$Sigma p$$ scattering experiment at J-PARC

赤澤 雄也*; 藤田 真奈美; 長谷川 勝一; 細見 健二; 市川 真也; 市川 裕大; 今井 憲一*; 七村 拓野; 成木 恵; 佐甲 博之; et al.

JPS Conference Proceedings (Internet), 33, p.011134_1 - 011134_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011134

We are performing a scattering experiment between a $$Sigma$$ hyperon and a proton (J-PARC E40) at the K1.8 beamline in the J-PARC Hadron Hall. The purpose of this experiment is to investigate the $$Sigma N$$ interaction by measuring the differential cross sections of the $$Sigma^+ p$$, $$Sigma^- p$$ elastic scatterings and $$Sigma^- p to Lambda n$$ inelastic scattering. The experimental data gives a strong constraint on the theoretical models of the $$Sigma N$$ interaction. The identification of $$Sigma p$$ scattering event with a high statistics is important by overcoming the difficulties in the hyperon proton scattering experiment. We have introduced a new identification method of the $$Sigma p$$ scattering event, which does not need to detect $$Sigma$$ particles directly. We used a new detector system called CATCH and two spectrometer systems installed at the upstream and the downstream of a liquid hydrogen target. A high intensity $$pi$$ beam of 20 M/spill was used to produce $$Sigma$$ particle. The momenta of $$pi$$ beam and scattered $$K^+$$ were measured by the spectrometers to reconstruct the momentum of a $$Sigma$$ beam produced via the $$pi p to Sigma K^+$$ reactions. The scattering angle and the kinetic energy of recoil protons from the $$Sigma p$$ scattering were measured by CATCH for the identification of the $$Sigma p$$ scattering events by checking the kinematic consistency. A part of the experiment was performed in 2018 and 2019 in J-PARC. As a result of analyzing the collected data, the $$Sigma^-$$ production and the $$Sigma^- p$$ scattering reaction have been identified. It means that our new measurement and analysis method are successfully working well. Analysis for deriving the differential cross section of the $$Sigma p$$ scattering is on going.

論文

Study of $$Lambda$$ identification method by the $$pi^-p to K^0Lambda$$ reaction for a $$Lambda p$$ scattering experiment at J-PARC

坂尾 珠和*; 藤田 真奈美; 長谷川 勝一; 細見 健二; 市川 真也; 市川 裕大; 今井 憲一*; 七村 拓野; 成木 恵; 佐甲 博之; et al.

JPS Conference Proceedings (Internet), 33, p.011133_1 - 011133_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011133

The $$pi^-p to K^0Lambda$$ reaction is an important elementary process to produce $$Lambda$$ from a proton target and is a key for a $$Lambda p$$ scattering experiment where the momentum of $$Lambda$$ should be tagged from the missing momentum of the $$(pi^-,K^0)$$ reaction. However, the $$(pi^-,K^0)$$ spectroscopy method has not been established yet due to the difficulty of the $$K^0$$ detection. Therefore, we have proposed a new $$K^0$$ detection method where $$pi^+$$ and $$pi^-$$ from the $$K^0$$ decay are measured by a forward magnetic spectrometer and a detector cluster surrounding the target, respectively. The feasibility of the $$K^0$$ detection method was confirmed by analyzing the J-PARC E40 data taken with such a detector system. In the analysis, $$Lambda$$'s were successfully identified in the missing mass spectrum of the $$pi^-p to K^0 X$$ reaction.

論文

Observation of Coulomb-assisted nuclear bound state of $$Xi^-$$-$$^{14}$$N system

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

https://doi.org/10.1103/PhysRevLett.126.062501
 被引用回数：34 パーセンタイル：94.71(Physics, Multidisciplinary)

In an emulsion-counter hybrid experiment performed at J-PARC, a $$Xi^-$$ absorption event was observed which decayed into twin single-$$Lambda$$ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as $$Xi^{-} + ^{14}$$N$$ rightarrow ^{10}_Lambda$$Be + $$^5_Lambda$$He. For the binding energy of the $$Xi^{-}$$ hyperon in the $$Xi^-$$-$$^{14}$$N system a value of $$1.27 pm 0.21$$ MeV was deduced. The energy level of $$Xi^-$$ is likely a nuclear $$1p$$ state which indicates a weak $${Xi}N$$-$$LambdaLambda$$ coupling.

論文

Study on the baryon interaction by $$Xi$$ hypernuclear spectroscopy with the $$(K^-, K^+)$$ reaction

後神 利志*; 藤田 真奈美; 長谷川 勝一; 細見 健二; 今井 憲一*; 市川 裕大; 七村 拓野; 成木 恵; 佐甲 博之; 佐藤 進; et al.

Journal of Physics; Conference Series, 1643, p.012133_1 - 012133_6, 2020/12

https://doi.org/10.1088/1742-6596/1643/1/012133
 被引用回数：2 パーセンタイル：83.94(Astronomy & Astrophysics)

We performed $$Xi$$ hypernuclear spectroscopy with the $$(K^-, K^+)$$ reaction at J-PARC to investigate the $$Xi N$$ interaction (J-PARC E05). A new experiment (J-PARC E70) in which a better energy resolution could be achieved is now being prepared. In this article, an analysis status of J-PARC E05 and a preparation status of J-PARC E70 are described.

論文

Study of $$Sigma N$$ interaction from the $$Sigma p$$ scattering experiment at J-PARC

三輪 浩司*; 藤田 真奈美; 長谷川 勝一; 細見 健二; 市川 真也; 市川 裕大; 今井 憲一*; 七村 拓野; 成木 恵; 佐甲 博之; et al.

Journal of Physics; Conference Series, 1643, p.012174_1 - 012174_6, 2020/12

https://doi.org/10.1088/1742-6596/1643/1/012174
 被引用回数：2 パーセンタイル：83.94(Astronomy & Astrophysics)

A high statistics $$Sigma p$$ scattering experiment has been performed at the K1.8 beamline in the J-PARC Hadron Experimental Facility. Data for momentum-tagged $$Sigma^-$$ beam running in a liquid hydrogen target were accumulated by detecting the $$pi^{-}p to {K}^{+}{Sigma}^{-}$$ reaction with a high intensity $$pi^-$$ beam of 20 M/spill. The number of the $$Sigma^-$$ beam was about $$1.7 times 10^7$$ in total. The $$Sigma^- p$$ elastic scattering and the $$Sigma^- p to Lambda n$$ inelastic scattering events were successfully observed with about 100 times larger statistics than that in past experiments.

論文

First $$gamma$$-ray spectroscopy of an $$sd$$-shell hypernucleus, $$^{19}_{Lambda}$$F

Yang, S. B.*; 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; 田村 裕和*; 谷田 聖; et al.

JPS Conference Proceedings (Internet), 26, p.023015_1 - 023015_5, 2019/11

https://doi.org/10.7566/JPSCP.26.023015

We performed a gamma-ray spectroscopy of $$({}_{Lambda}^{19}{rm F})$$ at J-PARC Hadron Experimental Facility in 2015. It is the first measurement of $$gamma$$ rays emitted from $$sd$$-shell hypernuclei. In this experiment, we determined the energy spacing between the ground state spin doublet, $$3/2^+$$ and $$1/2^+$$ states, as 316 keV. The excitation energies of $$5/2^+$$ and $$1/2^+$$ states are also determined to be 895 and 1266 keV, respectively. The energy spacing is found to be well reproduced by shell-model calculations which describe $$s$$- and $$p$$-shell $$Lambda$$ hypernuclei well. The results show that the present theories of the $$Lambda N$$ interaction describe not only the light hypernuclei but also a heavier hypernucleus.

論文

A $$Sigma p$$ scattering experiment at J-PARC and the analysis status

中田 祥之*; 長谷川 勝一; 早川 修平*; 細見 健二; 市川 裕大; 今井 憲一; 七村 拓野*; 成木 恵*; 佐甲 博之; 佐藤 進; et al.

JPS Conference Proceedings (Internet), 26, p.023024_1 - 023024_5, 2019/11

https://doi.org/10.7566/JPSCP.26.023024

J-PARC E40 aims to measure the differential cross sections of the $$Sigma^{pm}p$$ elastic scatterings and the $$Sigma^-p to Lambda n$$ conversion. A clear peak of $$Sigma^-$$ was observed in a missing mass spectrum of the $$pi^-pto K^+X$$ reaction and recoil protons from the $$pi p$$ elastic scattering were successfully observed in the data taken in the summer 2018. The rest of data taking is coming in the spring 2019.

論文

Study of $$Y^*$$ in nuclei through C$$(K^-, pi^+)X$$ spectrum at 1.8 GeV/$$c$$ in the J-PARC E05 experiment

本多 良太郎*; 長谷川 勝一; 早川 修平; 細見 健二; 今井 憲一; 市川 裕大; 七村 拓野; 成木 恵; 佐甲 博之; 佐藤 進; et al.

JPS Conference Proceedings (Internet), 26, p.023014_1 - 023014_4, 2019/11

https://doi.org/10.7566/JPSCP.26.023014

We measured the $$(K^-,pi^+)$$ reaction spectra at 1.8 GeV/$$c$$ for the graphite and the polyethylene targets in the J-PARC E05 pilot experiment. By comparing the spectra for these two targets, it was found that $$Sigma^{*-}(1385)$$ in the $$^{11}$$B nucleus is quite broadened. Furthermore, we also compared broadness of $$Sigma^{*-}(1385)$$ with $$K^*(892)$$ obtained in the $$(K^-,p)$$ spectrum. $$Sigma^{*-}(1385)$$ seems to be much more broadened in nuclei than $$K^*(892)$$. We gave a possible interpretation, which is related to compositeness of decuplet baryons, for this situation.

論文

Search for excited state of $$_{Sigma }^{4}{rm He}$$ hypernucleus in the J-PARC E13 experiment

中川 真菜美*; 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; 田村 裕和; 谷田 聖; et al.

JPS Conference Proceedings (Internet), 26, p.023005_1 - 023005_3, 2019/11

https://doi.org/10.7566/JPSCP.26.023005

The $$Sigma N$$ interaction is not much studied than the $$Lambda N$$ interaction. To understand the $$Sigma N$$ interaction, we study $$Sigma$$ hypernuclei. As for the $$Sigma$$ hypernucleus, only the ground state of $$_{Sigma }^{4}{rm He}$$ has been observed. To obtain more information about the $$Sigma N$$ interaction, the excited state should be studied. Therefore, we measure the missing-mass of the $$^4$$He$$(K^-,pi^-)$$ reaction at $$p_{K^-} = 1.5$$ GeV/$$c$$ and $$theta_{rm Lab} =$$ 2-14$$^{circ}$$ at the J-PARC K1.8 beam line. The ground state of $$_{Sigma }^{4}{rm He}$$ is observed whereas a peak of the excited states is not observed. We also observe suppression of the $$Sigma$$ quasi-free process at smaller angles.

論文

Observation of a $$Xi$$ bound state in the $$^{12}$$C$$(K^-, K^+)$$ reaction at 1.8 GeV/$$c$$

永江 知文*; 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; 金原 慎二; 七村 拓野*; 成木 恵; et al.

AIP Conference Proceedings 2130, p.020015_1 - 020015_9, 2019/07

https://doi.org/10.1063/1.5118383
 被引用回数：12 パーセンタイル：98.06(Physics, Nuclear)

For the full understanding of baryon-baryon interactions in flavor $$SU(3)$$, the $$Xi N$$ interaction is the last missing piece of information. So far, we have revealed the $$Lambda N$$ interaction to be attractive ($$U_{Lambda} cong 30$$ MeV), and $$Sigma N$$ interaction to be repulsive in the medium to heavy mass-number region. The $$Lambda Lambda$$ bonding energy is weakly attractive. While we have a few experimental observations suggesting the $$Xi N$$ interaction would be attractive, there still exist large theoretical ambiguities weather it is attractive or not. Experimental determinations on the existence of bound states of $$Xi$$ hypernuclei by observing bound-state peaks are strongly awaited. In this report, a new preliminary result on the missing-mass spectrum of a $$^{12}$$C$$(K^-, K^+)$$ reaction, which strongly suggests the existence of $$Xi$$-hypernuclear bound states, is presented.

論文

Gamma-ray spectroscopy of single $$Lambda$$-hypernuclei at J-PARC; Results and perspective

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

https://doi.org/10.1063/1.5118379
 被引用回数：2 パーセンタイル：72.56(Physics, Nuclear)

Experimental results from the J-PARC E13 experiments are summarized. A new experimental set up of E13 has established a platform for the future $$gamma$$-ray hypernuclear spectroscopy at J-PARC using kaon beams. New $$gamma$$ rays are identified in $$^4_{Lambda}$$He and $$^{19}_{Lambda}$$F. The energy of 1.406 MeV for the $$^4_{Lambda}$$He$$(1^+ to 0^+)$$ transition confirmed a sizable effect of Charge Symmetry Breaking (CSB) in $$Lambda N$$ interaction in the $$A=4$$ hypernuclear system. The identification of four $$gamma$$ rays in $$^{19}_{Lambda}$$F is made for the first time in $$sd$$ 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 $$p$$ shell hypernuclei is also applicable to heavier hypernuclei. Lastly, an overview of the future J-PARC E63 experiment is given.

論文

Observation of a Be double-Lambda hypernucleus in the J-PARC E07 experiment

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

https://doi.org/10.1093/ptep/pty149
 被引用回数：25 パーセンタイル：83.09(Physics, Multidisciplinary)

A double-$$Lambda$$ hypernucleus, $${}_{LambdaLambda}mathrm{Be}$$, was observed by the J-PARC E07 collaborationin nuclear emulsions tagged by the $$(K^{-},K^{+})$$ reaction. This event was interpreted as a production and decay of $$ {}_{LambdaLambda}^{;10}mathrm{Be}$$,$${}_{LambdaLambda}^{;11}mathrm{Be}$$, or $${}_{LambdaLambda}^{;12}mathrm{Be}^{*}$$ via $$Xi^{-}$$ capture in $${}^{16}mathrm{O}$$.By assuming the capture in the atomic 3D state, the binding energy of two $$Lambda$$ hyperons$$,$$($$B_{LambdaLambda}$$)of these double-$$Lambda$$ hypernuclei are obtained to be$$15.05 pm 0.11,mathrm{MeV}$$, $$19.07 pm 0.11,mathrm{MeV}$$, and $$13.68 pm 0.11,mathrm{MeV}$$, respectively. Based on the kinematic fitting, $${}_{LambdaLambda}^{;11}mathrm{Be}$$ is the most likely explanation for the observed event.

論文

First determination of the level structure of an $$sd$$-shell hypernucleus, $$^{19}_{Lambda}$$F

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

AA2018-0124.pdf:0.62MB

https://doi.org/10.1103/PhysRevLett.120.132505
 被引用回数：8 パーセンタイル：53.69(Physics, Multidisciplinary)

We report on the first observation of $$gamma$$ rays emitted from an $$sd$$-shell hypernucleus, $$^{19}_{Lambda}$$F. The energy spacing between the ground state doublet, $$1/2^+$$ and $$3/2^+$$ states, of $$^{19}_{Lambda}$$F is determined to be $$315.5pm0.4({rm stat.})^{+0.6}_{-0.5}({rm syst.})$$ keV by measuring the $$gamma$$-ray energy of the $$M1(3/2^+ to 1/2^+)$$ transition. In addition, three $$gamma$$-ray peaks are observed and assigned as $$E2(5/2^+ to 1/2^+)$$, $$E1(1/2^- to 1/2^+)$$, and $$E1(1/2^- to 3/2^+)$$ transitions. The excitation energies of the $$5/2^+$$ and $$1/2^-$$ states are determined to be $$895.2pm0.3({rm stat.})pm0.5({rm syst.})$$ keV and $$1265.6pm1.2({rm stat.})^{+0.5}_{-0.7}({rm syst.})$$ keV, respectively. It is found that the ground state doublet spacing is well described by theoretical models based on existing $$s$$- and $$p$$-shell hypernuclear data.

論文

Spectroscopy of nuclei with multi-strangeness by using new S-2S spectrometer at J-PARC

後神 利志*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 今井 憲一; 市川 裕大; 七村 拓野; 成木 恵; 佐甲 博之; et al.

JPS Conference Proceedings (Internet), 18, p.011031_1 - 011031_6, 2017/11

https://doi.org/10.7566/JPSCP.18.011031

The missing mass spectroscopy of $$Xi^-$$ hypernuclei is planned at the Japan Proton Accelerator Research Complex (J-PARC) by using the $$(K^-,K^+)$$ reaction. We are constructing a new magnetic spectrometer, S-2S, which has a better momentum resolution [$$Delta p/p = 5 times 10^{-4}$$ (FHWM)] than that of an existing spectrometer (SKS) at J-PARC. S-2S would give us an opportunity to confirm the existence of $$Xi^-$$ hypernuclei as a peak structure owing to both the high momentum resolution and its reasonably large solid angle. Brief descriptions of our experiment and of its preparation status are presentedin this article.

論文

The First gamma-ray spectroscopic study of $$sd$$-shell hypernucleus, $$^{19}_{Lambda}$$F

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

https://doi.org/10.7566/JPSCP.17.012004

The first $$gamma$$-ray spectroscopy of $$sd$$-shell hypernucleus, $$^{19}_{Lambda}$$F, is performed in June, 2015 at the J-PARC K1.8 beam line (J-PARC E13). Precise energy levels of $$^{19}_{Lambda}$$F can be revealed by measured $$gamma$$ rays in this experiment. Especially, the strength of $$Lambda N$$ spin-spin interaction in $$sd$$-shell hypernucleus is obtained through the energy spacing of the ground-state doublet of the hypernucleus. By comparing its strength between the $$s$$, $$p$$, and $$sd$$-shell hypernuclei, a radial dependence $$Lambda N$$ interaction is investigated. The hypernucleus is produced through the $$(K^-,pi^-)$$ reaction with the beam momentum of 1.8 GeV/c. In very preliminary results, we observed two $$gamma$$ rays, and their energies are $$315.8 pm 0.4$$ keV and $$ 895.3 pm 0.3$$ keV where the uncertainties are only statistical.

論文

High statistics $$Sigma p$$ scattering experiment using high intensity pion beams at J-PARC

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

https://doi.org/10.7566/JPSCP.17.041002

In order to test theoretical frameworks of the Baryon-Baryon ($$BB$$) 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 $$Sigma^+ p$$, $$Sigma^- p$$ elastic scatterings and the $$Sigma^- p to Lambda n$$ inelastic scattering in the momentum range of $$400 < p ; ({rm MeV}/c) < 700$$ in the laboratory system. Experimentally, we detect two successive reactions of the $$Sigma$$ production $$(pi^{pm}p to K^+Sigma^{pm})$$ and the $$Sigma p$$ scattering ($$Sigma p to Sigma p$$) 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 $$pi$$ 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 $$BB$$ interaction.

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