VI. RNC ACTIVITIESRIKEN Accel. Prog. Rep. 54 (2021)

Subnuclear System Research Division
Meson Science Laboratory
1. Abstract

Particles like muons, pions, and kaons have finite life times, so they do not exist in natural nuclei or matters. By implanting theseparticles into nuclei/matters, exotic phenomena in various objects can be studied from new point of view.
For example, kaon is the second lightest meson, which has strange quark as a constituent quark. It is expected that if one embeds
mesons into nuclei, the sizes of the nuclei become smaller and one can form a high-density object beyond the normal nuclear density.
Study of this object could lead to better understanding of the origin of the mass of the matter, and may reveal the quark degree of
freedom beyond the quark-confinement. The other example is the weak interaction in nuclear matter. It can only be studied by the
weak decay of hypernuclei, which have Lambda particle in the nuclei.
Muon provides even wider scope of studies, covering condensed matter physics as well as nuclear and atomic physics, and weare trying to extend the application field further into chemical and biological studies. For instance, stopping positively charged muonin a material, we obtain information on the magnetic properties or the local field at the muon trapped site (µSR). Injecting negatively
charged muon to hydrogen gas, muonic hydrogen atom (µp) is formed. We are planning to measure µp hyperfine splitting energy tomeasure proton magnetic radius, which is complementary quantity to the proton charge radius and its puzzle. We are also interested
in precision measurement of muon property itself, such as muon anomalous magnetic moment (g − 2).
In our research, we introduce diﬀerent kind of impurities into nuclei/matters, and study new states of matter, new phenomena, or
the object properties.

2. Major Research Subjects
(1)
(2)
(3)
(4)
(5)

Study of meson property and interaction in nuclei
Origin of matter mass/quark degree of freedom in nuclei
Condensed matter and material studies with muon
Nuclear and particle physics studies via muonic hydrogen
Development of ultra cold muon beam, and its application from material science to particle physics

3. Summary of Research Activity(1) Hadron physics at J-PARC, RIKEN-RIBF, GSI and SPring-8
Kaon and pion will shed a new insight to the nuclear physics. The recent discovery of deeply bound pionic atom enables us toinvestigate the properties of mesons in nuclear matter. At RIKEN-RIBF, we are preparing precise experimental study of the pionicatom. Very lately, we succeeded to discover kaonic nuclear bound state, “K − pp,” at J-PARC. The yield dependence on momentumtransfer shows that observed system is unexpectedly small. We extended our study on Λ(1405) that could be K-p bound state. By theseexperiments, we are studying the KN − interaction, and clarify the nature of kaon in nuclei. At Spring-8 and at GSI, we are planning tostudy omega and η′ nuclei. By these experiments, we aim to be a world-leading scientific research group using these light meta-stableparticles.
(1-1) Deeply bound kaonic nuclei
J-PARC E15 experiment had been performed to explore the simplest kaonic nuclear bound state, “K − pp.” Because of the strong
attraction between KN − , the K − in nuclei may attract surrounding nucleons, resulting in forming a deeply bound and extremely dense
object. Measurement of the kaon properties at such a high-density medium will provide precious information on the origin of hadron
masses, if the standard scenario of the hadron-mass-generation mechanism, in which the hadron masses are depends on matter densityand energy, is correct. Namely, one may study the chiral symmetry breaking of the universe and its partial restoration in nuclear
medium.
The E15 experiment was completed to observe the “K − pp” bound state by the in-flight 3 He(K − , n) reaction, which allows us
the formation via the invariant-mass spectroscopy by detecting decay particles from “K − pp.” For the experiment, we constructed a
dedicated spectrometer system at the secondary beam-line, K1.8BR, in the hadron hall of J-PARC.
With the Λpn final states obtained in the first stage experiment, we observed a kinematic anomaly in the Λp invariant mass
near the mass threshold of M(K − pp) (total mass of kaon and two protons) at the lower momentum transfer q region. We conducteda successive experiment to examine the nature of the observed kinematical anomaly in the Λpn final state, and we confirmed theexistence of the bound state below the mass threshold of M(K − pp) at as deep as the binding energy of 40 MeV. The momentum
transfer q naturally prefers lower momentum for the bound state formation, but the observed event concentration extended having theform-factor parameter ∼400 MeV/c. Based on the PWIA calculation, the data indicated that the “K − pp” system could be as small as∼0.6 fm. It is astonishingly compact in contrast to the mean nucleon distance ∼1.8 fm.
This observed signal shows that a meson (qq− ) forms a quantum state where baryons (qqq) exist as nuclear medium, i.e., ahighly excited novel form of nucleus with a kaon, in which the mesonic degree-of-freedom still holds. This is totally new form of
nuclear system, which never been observed before.
(1-2) Precision X-ray measurement of kaonic atom
To study the KN − interaction at zero energy from the atomic state level shift and width of kaon, we have performed an X-ray
spectroscopy of atomic 3d → 2p transition of negatively charged K-mesons captured by helium atoms. However, our first experimentis insuﬃcient in energy resolution to see the K − -nucleus potential. Aiming to provide a breakthrough from atomic level observation,- 314 -

VI. RNC ACTIVITIESRIKEN Accel. Prog. Rep. 54 (2021)

we introduce a novel X-ray detector, namely superconducting transition-edge-sensor (TES) microcalorimeter oﬀering unprecedented
high energy resolution, being more than one order of magnitude better than that achieved in the past experiments using conventional
semiconductor detectors. The experiment J-PARC E62 aims to determine 2p-level strong interaction shifts of kaonic 3 He and 4 He
atoms by measuring the atomic 3d → 2p transition X-rays using TES detector with 240 pixels having about 23 mm2 eﬀective area
and the average energy resolution of 7 eV (FWHM) at 6 keV. We carried out the experiment at J-PARC in June 2018 and successfully
observed distinct X-ray peaks from both atoms. The data analysis is now ongoing.
Another important X-ray measurement of kaonic atom would be 2p → 1s transition of kaonic deuteron (K − -d). We have measured
same transition of kaonic hydrogen (K − -p), but the width and shift from electro-magnetic (EM) value reflect only isospin average ofthe KN interaction. We can resolve isospin dependence of the strong interaction by the measurements both for K − -p and K − -d. The
experiment J-PARC E57 aims at pioneering measurement of the X-rays from K − -d atoms. Prior to full (stage-2) approval of the E57
proposal, we performed a pilot run with hydrogen target in March 2019.
(1-3) Deeply bound pionic atoms and η′ mesonic nuclei
We have been working on precision spectroscopy of pionic atoms systematically, which leads to understanding of the non-trivial
structure of the vacuum and the origin of hadron masses. The precision data set stringent constraints on the chiral condensate at
nuclear medium. We are presently preparing for the precision systematic measurements at RIBF. A pilot experiment performed in2010 showed a unprecedented results of pionic atom formation spectra with finite reaction angles. The measurement of pionic 121 Sn
performed in 2014 showed a very good performance of the system. We have been finalizing the data analysis to achieve informationon the pion-nucleus interaction based on the pionic atom spectroscopy. At the same time we have been working on a systematic highprecision spectroscopy of pionic tin isotopes.
We are also working on spectroscopy of η′ mesonic nuclei in GSI/FAIR. Theoretically, peculiarly large mass of η′ is attributed
to UA(1) symmetry and chiral symmetry breaking. As a result, large binding energy is expected for η′ meson bound states in nuclei(η′ -mesonic nuclei). From the measurement, we can access information about gluon dynamics in the vacuum via the binding energy
and decay width of η′ -nuclear bound state. We are preparing for a new experiment using a large solid angle detectors at GSI.
(1-4) 3Λ H lifetime puzzle and our approach
Three recent heavy ion experiments (HypHI, STAR, and ALICE) announced surprisingly short lifetime for 3Λ H hyper-nucleus’s
Mesonic Weak Decay (MWD), which seems to be inconsistent with the fact that the 3Λ H is a very loosely bound system. It is very
interesting to study this with a diﬀerent experimental approach. We proposed a direct measurement of 3Λ H MWD lifetime with ∼20%
resolution at J-PARC hadron facility by using K − meson beam at 1 GeV/c. As for the feasibility test, we also measure 4Λ H lifetime.
A Cylindrical Detector System (CDS) used in J-PARC E15/E31 experiment is employed to capture the delayed π− as a weak decay
product from 3,Λ4 H a calorimeter is installed in the very forward region to tag fast π0 meson emission at ∼0 degree, which ensures thatthe Λ hyperon production with small recoil momentum. By this selection, we can improve the ratio between 3,Λ4 H and quasi-free Λ andΣ background. A test beam for feasibility study with 4 He target has been conditionally approved by J-PARC PAC. We will conduct
the experiment and to present the data in short.
(2) Muon science at RIKEN-RAL branch
The research area ranges over particle physics, condensed matter studies, chemistry and life science. Our core activities are
based on the RIKEN-RAL Muon Facility located at the Rutherford-Appleton Laboratory (UK), which provides intense pulsed-muonbeams. We have variety of important research activities such as particle/nuclear physics studies with muon’s spin and condensed
matter physics by muon spin rotation/relaxation/resonance (µSR).
(2-1) Condensed matter/materials studies with µSR
We stated to share experimental equipment with those of RAL in order to make organization of RIKEN beam time schedules
easier and to enhance the eﬃciency to carry out RIKEN’s experiments. We use shared cryostats and manpower supports available
from RAL as well we other experimental areas. Both two µSR spectrometers, ARGUS (Port-2) and CHRNUS (Port-4), are working
wel wit maintenance supports provide from RAL. Among our scientific activities on µSR studies from year 2017 to 2020, following
studies are most important subjects of material sciences at the RIKEN-RAL muon facility:(1) Multi magnetic transitions in the Ru-based pyrochlore systems, R2 Ru2 O7 .
(2) Magnetic properties of the nano-cluster gold in the border of macro- and micro- scale.
(3) Novel magnetic and superconducting properties of nano-size La-based high-T c superconducting curates.
(4) Determination of muon positions estimated from density functional theory (DFT) and dipole-field calculations.
(5) Chemical muonic states in DNA molecules.
(2-2) Nuclear and particle physics studies via ultra-cold muon beam and muonic atoms
If we can improve muon beam emittance, timing and energy dispersion (so-called “ultra-cold muon”), then the capability of µSR
studies will be drastically improved. The ultra-cold muon beam can stop in a thin foil, multi-layered materials and artificial lattices, so
one can apply the µSR techniques to surface and interface science. The development of ultra-cold muon beam is also very importantas the source of pencil-like small emittance muon beam for muon g − 2 measurement.
Ultra-cold muon beam has been produced by laser ionization of muoniums in vacuum (bound system of µ+ and electron). We
are developing two key components, high eﬃciency muonium generator at room temperature and high intensity ionization laser. The
study of muonium generator has been done in collaboration with TRIUMF. In 2013, we demonstrated at least 10 times increase of
the muonium emission eﬃciency by fabricating fine laser drill-holes on the surface of silica aerogel. Further study was done in 2017with more than 20 aerogel target having diﬀerent surface conditions. We are analyzing the data to identify which condition mostcontributed to increasing the muonium emission eﬃciency. We also developed a high power Lyman-α laser in collaboration with laser- 315 -

VI. RNC ACTIVITIESRIKEN Accel. Prog. Rep. 54 (2021)

group at RIKEN. In this laser development, we succeeded to synthesize novel laser crystal Nd:YGAG, which has an ideal wavelength
property for laser amplification to generate Lyman-α by four-wave mixing in Kr gas cell. We already achieved 10 times increase of
Lyman-α generation than before. However, in order to increase the intensity by one more order, we need a larger size crystal. So far
we have inhomogeneity problem but we are trying to solve this problem.
A large discrepancy was found recently in the proton charge radius between the new precise value from muonic hydrogen atom at
PSI and the values from normal hydrogen spectroscopy and e-p scattering. We are planning a precise measurement of proton Zemachradius (with charge and magnetic distributions combined) using the laser spectroscopy of hyperfine splitting energy in the muonichydrogen atom. As a key parameter for designing the experiment, we need to know the quench rate of the muonic proton polarization
due to collision with surrounding protons, for which only theoretical estimations are available. We first measured the quench rate ofmuonic deuterium polarization in deuterium gas, which confirmed the long lifetime consistent with the calculation. We also carriedout measurement on muonic proton in low pressure hydrogen gas and the analysis is in progress.

Members
Director
Masahiko IWASAKI
Research Scientists
Kenta ITAHASHI (Senior Research Scientist)
Yue MA (Senior Research Scientist)
Haruhiko OUTA (Senior Research Scientist)

Fuminori SAKUMA (Senior Research Scientist)
Isao WATANABE (Senior Research Scientist)

Contract Researcher
Katsuhiko ISHIDA
Junior Research Associates
Shun SEO (Univ. of Tokyo)

Muhamad D. UMAR (Hokkaido Univ.)

International Program Associates
Muhammad H.B. CHE LAH (Univ. Sains Malaysia)
Harison B. ROZAK (Univ. Sains Malaysia)

Suci WINARSIH (Univ. Indonesia)
Utami WIDYAISWARI (Univ. Indonesia)

Research Consultant
Masayasu KAMIMURA
Senior Visiting Scientists
Hiroyuki NOUMI (Osaka Univ.)

Kazuhiro TANAKA (KEK)

Visiting Scientists
Tadashi ADACHI (Sophia Univ.)
Hiroko ARIGA (Hokkaido Univ.)
Retno ASIH (Inst. Teknologi Sepuluh Nopember)
Fahmi ASTUTI (Inst. Teknologi Sepuluh Nopember)
KwangYong CHOI (Chung-Ang Univ.)
Catalina Oana CURCEANU (INFN)
Zyun EZAWA (Tohoku Univ.)
Hiroyuki FUJIOKA (Tokyo Tech)
Masaki FUJITA (Tohoku Univ.)
Shuhei FUKUOKA (Hokkaido Univ.)
Takayuki GOTO (Sophia Univ.)
Maryam HASSANVAND (Isfahan Univ. of Tech.)
Wataru HIGEMOTO (JAEA)
Ko-ichi HIRAKI (Fukushima Medical Univ.)
Satoru HIRENZAKI (Nara Women’s Univ.)
Koichi ICHIMURA (Hokkaido Univ.)
Yasuyuki ISHII (Shibaura Inst. of Tech.)
Ryosuke KADONO (KEK)
Takayuki KAWAMATA (Tohoku Univ.)
Seiko KAWAMURA (JAEA)
Hikomitsu KIKUCHI (Univ. of Fukui)
Takuya KOBAYASHI (Saitama Univ.)
Yoji KOIKE (Tohoku Univ.)
Seungwon LEE (Univ. of Toyama)

Kenji MATSUDA (Univ. of Toyama)
Hiroyasu MATSUURA (Univ. of Tokyo)
Mototsugu MIHARA (Osaka Univ.)
Takaaki MINAMIDATE (Tokyo Univ. of Sci)
Yasuhiro MIYAKE (KEK)
Mohamed Ismail MOHAMED-IBRAHIM (Univ. Sains
Malaysia)
Takehito NAKANO (Ibaraki Univ.)
Takahiro NAMIKI (Univ. of Toyama)
Katsuhiko NISHIMURA (Univ. of Toyama)
Yasuo NOZUE (Osaka Univ.)
Agustinus NUGROHO (Inst. Teknologi Bandung)
Kazuki OHISHI (Comprehensive Res. Org. for Sci. and Soc.)
Yu OISHI (KEK)
Atsushi OKAZAWA (Univ. of Tokyo)
Dita PUSPITA SARI (Shibaura Inst. of Tech.)Irwan RAMLI (Univ. Cokroaminoto Palopo)
RISDIANA (Padjadjaran Univ.)
Lusi SAFRIANI (Padjadjaran Univ.)
Naohito SAITO (KEK)
Shinichi SHAMOTO (CROSS)
Ichiro SHIRAKI (Univ. of Yamanashi)
Shukri SULAIMAN (Univ. Sains Malaysia)
Ken SUZUKI (Stefan Meyer Inst.)- 316 -

VI. RNC ACTIVITIESRIKEN Accel. Prog. Rep. 54 (2021)

Kensuke SUZUKI (Tohoku Univ.)
Takao SUZUKI (Shibaura Inst. of Tech.)
Hiroshi TANIDA (Toyama Prefectural Univ.)
Takanori TANIGUCHI (Tohoku Univ.)
Andrea VACCHI (Udine Univ. (Italy))
Eberhard WIDMANN (Stefan Meyer Inst.)
Zhuan XU (Zhejiang Univ.)
Yasuhiro YAMAGUCHI (JAEA)

Ichihiro YAMAUCHI (Saga Univ.)
Toshimitsu YAMAZAKI (Univ. of Tokyo)
Yukio YASUI (Meiji Univ.)
Masaru YOSOI (Osaka Univ.)
Wan Nurfadhilah B. ZAHARIM (Univ. Sains Malaysia)
Xu-Guang ZHENG (Saga Univ.)
Johann ZMESKAL (Austrian Academy of Sci.)

Student Trainees
Redo Muhammad RAMADHAN (Univ. Indonesia)
Harison B. ROZAK (Univ. Sains Malaysia)
Yuki SAGARA (Shibaura Inst. of Tech.)Ryo SASAKI (Shibaura Inst. of Tech.)
SUCI WINARSIH (Univ. Indonesia)

Assistants
Kumiko TAKAHASHI

Mitsue YAMAMOTO

List of Publications & Presentations
Publications[Original Papers]
J. Sugiyama, O. Kenji Forslund, E. Nocerino, N. Matsubar, K. Papadopoulos, Y. Sassa, Stephen P. Cottrell, Adrian D. Hillier, K. Ishida,
M. Mansson, and J. H. Brewer, “Lithium diﬀusion in LiMnPO4 detected with µ± SR,” Phys. Rev. Research 2, 033161 (2020).
M. Aramini, C. Milanese, Adrian D. Hillier, A. Girella, C. Horstmann, T. Klassen, K. Ishida, M. Dornheim, and C. Pistidda, “Spectroscopic tool for the investigation of the local chemistry of elements,” Nanomaterials 2020, 10, 1260 (2020).
E. Mocchiutti, A. Adamczak, D. Bakalov, G. Baldazzi, R. Benocci, R. Bertoni, M. Bonesini, V. Bonvicini, H. CabreraMorales, F. Chignoli, M. Clemenza, L. Colace, M. Danailov, P. Danev, A. de Bari, C. DeVecchi, M. DeVincenzi, E. Furlanetto, F. Fuschinod,
K. S. Gadedjisso-Tossoua, D. Guﬀantia, K. Ishida, C. Labanti, V. Maggi, R. Mazza, A. Menegolli, G. Morgante, M. Nastasi, J. Niemela,
C. Pizzolotto, A. Pullia, R. Ramponi, L. P. Rignanese, M. Rossella, N. Rossi, M. Stoilov, L. Stoychev, L. Tortora, E. Vallazza, G. Zampa,
and A. Vacchi, “First measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen,” Phys.
Lett. A 384, 126667 (2020).
C. Pizzolotto, A. Adamczak, D. Bakalov, G. Baldazzi, M. Baruzzo, R. Benocci, R. Bertoni, M. Bonesini, V. Bonvicini, H. Cabrera,
D. Cirrincione, M. Citossi, F. Chignoli, M. Clemenza, .Colace,. Danailov, P. Danev, A. de Bari, C. De Vecchi, M. de Vincenzi, E. Fasci,
E. Furlanetto,. Fuschino, K. S. Gadedjisso-Tossou, L. Gianfran, D. Guﬀanti, A. D. Hillier, K. Ishida,. J. C. King, C. Labanti, V. Maggi,
R. Mazza, A. Menegolli, E. Mocchiutti, L. Moretti,. Morgante, J. Niemela, B. Patrizi, A. Pirri, A. Pullia, R. Ramponi, L. P. Rignanese,
E. Roman,. Rossella, R. Sarkar, A. Sbrizzi,. Stoilov, L. Stoychev, J. J. Suárez-Vargas, G. Toci, L. Tortora, E. Vallazza, M. Vannini,
C. Xiao, G. Zampa, and A. Vacchi1, “The FAMU experiment: muonic hydrogen high precision spectroscopy studies,” Eur. Phys. J. A
56, 185 (2020).
J. Beare, G. Beer, J. H. Brewer, T. Iijima, K. Ishida, M. Iwasaki, S. Kamal, K. Kanamori, N. Kawamura, R. Kitamura, S. Li, G. M. Luke,
G. M. Marshall, T. Mibe, Y. Miyake, Y. Oishi, K. Olchanski, A. Olin, M. Otani, M. A. Rehman, N. Saito, Y. Sato, K. Shimomura,
K. Suzuki, M. Tabata, and H. Yasuda, “Study of muonium emission from laser-ablated silica aerogel,” Prog. Theor. Exp. Phys. 2020,
123C01 (2020).
H. Yamauchi, D. P. Sari, I. Watanabe, Y. Yasui, L. -J. Chang, K. Kondo, T. U. Ito, M. Ishikado, M. Hahara, M. D. Frontzk, C. Chi,
J. A. Fernandez-Bac, J. S. Lord, A. Berlie, A. Kotani, S. Mori, and S. Shamoto, “High-temperature short-range order in Mn3 RhSi,”
Commun. Matter. 1, 42 (2020).
M. Fujita, K. M. Suzuki, S. Asano, H. Okabe, A. Koda, R. Kadono, and I. Watanabe, “Magnetic behavior of T ’-type Eu2 CuO4 revealed
by muon spin rotation and relaxation measurements,” Phys. Rev. B 102, 045116 (2020).
R. Kitamura, S. Bae, S. Choi, Y. Fukao, H. Iinuma, K. Ishida, N. Kawamura, B. Kim, Y. Kondo, T. Mibe, Y. Miyake, M. Otani, G. P. Razuvaev, N. Saito, K. Shimomura, and P. Strasser, “Development of negative muonium ion source for muon acceleration,” Phys. Rev. Accel.
Beams 24, 033403 (2021).
S. Kanda, Y. Fukao, Y. Ikedo, K. Ishida, M. Iwasaki, D. Kawall, N. Kawamura, K. M. Kojima, N. Kurosawa, Y. Matsuda, T. Mibe,
Y. Miyake, S. Nishimura, N. Saito, Y. Sato, S. Seo, K. Shimomura, P. Strasser, K. S. Tanaka, T. Tanaka, H. A. Torii, A. Toyoda, andY. Ueno, “New precise spectroscopy of the hyperfine structure in muonium with a high-intensity pulsed muon beam,” Phys. Lett. B
815, 136154 (2021).
A. D. Pant, K. Ishida, N. Kawamura, S. Matoba, A. Koda, S. Nishimura, and K. Shimomura, “Study of muonium behavior in n-typesilicon for generation of ultra cold muonium in vacuum,” Physica B 613, 412997 (2021).
T. Yamaga et al., “Observation of a KNN bound state in the 3 He(K − , Λp)n reaction,” Phys. Rev. C 102, 044002 (2020).

[Proceedings]
F. Sakuma et al., “K − pp bound system at J-PARC,” AIP Conference Proceedings 2249, 020005 (2020).
F. Sakuma et al., “K-nuclear bound state at J-PARC,” JPS Conf. Proc. 32, 010088 (2020).
H. Fujioka, K. Itahashi, V. Metag, M. Nanova, and Y. K. Tanaka, “Comment on ‘Search for η′ bound nuclei in the 12 C(γ, p) reaction withsimultaneous detection of decay products’,” Phys. Rev. Lett. 126, 019201 (2021).

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VI. RNC ACTIVITIESRIKEN Accel. Prog. Rep. 54 (2021)

A. Tani, N. Ikeno, D. Jido, H. Nagahiro, H. Fujioka, K. Itahashi, and S. Hirenzaki, “Structure of double pionic atoms,” PTEP 2021, 3,
033D02 (2021).

Presentations[International Conferences/Workshops]
F. Sakuma (plenary), “Recent results and future prospects of kaonic nuclei at J-PARC,” Yamada Conference LXXII: The 8th Asia-PacificConference on Few-Body Problems in Physics (APFB2020), Kanazawa, Japan, March 1–5, 2021.
T. Yamaga (invited), “Observation of the K − pp bound state in J-PARC E15,” Hadron in Nucleus 2020 (HIN20), Kyoto, Japan, March
8–10, 2021.
T. Hashimoto (invited), “Kaonic atom experiments at J-PARC,” Hadron in Nucleus 2020 (HIN20), Kyoto, Japan, March 8–10, 2021.
Y. Ma (invited), “Towards solving the hypertriton lifetime puzzle with direct lifetime measurement: current status of J-PARC E73 experiment,” Hadron in Nucleus 2020 (HIN20), Kyoto, Japan, March 8–10, 2021.

[Domestic Conferences/Workshops]
石田勝彦, 「英国理研 RAL ミュオン施設におけるミュオン利用分析研究の進展」, 第 3 回 文理融合シンポジウム 量子ビームで歴史を探る—加速器が紡ぐ文理融合の地平—, オンライン, 2020 年 9 月 25–26 日.
石田勝彦 (招待講演), 「理研 RAL と J-PARC」, パルス中性子ミュオン発生 40 周年記念シンポジウム, オンライン, 2020 年 12 月
23 日.
石田勝彦, 「理研 RAL での非破壊元素分析」, 第 4 回文理融合シンポジウム 量子ビームで歴史を探る—加速器が紡ぐ文理融合の地平—, オンライン, 2021 年 1 月 28–29 日.
佐久間史典（口頭発表）, 「軽い K 中間子原子核の系統的測定」, 日本物理学会 第 76 回年次大会, オンライン, 2021 年 3 月 12–15 日.
0

山我拓巳（口頭発表）, 「K − pp のスピン・パリティ測定と K nn の探索」, 日本物理学会第 76 回年次大会, オンライン, 2021 年 3 月
12–15 日.
浅野秀光 （口頭発表）, 「K − d 反応の運動量移行と π± Σ ± 不変質量分布の関係」, 日本物理学会 第 76 回年次大会, オンライン, 2021
年 3 月 12–15 日.
橋本直 （口頭発表）, 「TES マイクロカロリメータを用いた K 中間子ヘリウム原子 X 線精密分光」, 日本物理学会 第 76 回年次大会, オンライン, 2021 年 3 月 12–15 日.
赤石貴也 （口頭発表）, 「K − ビームを用いたハイパートライトンの寿命直接測定の現状」, 日本物理学会 第 76 回年次大会, オンラ
イン, 2021 年 3 月 12–15 日.
赤石貴也 （口頭発表）, 「3Λ H 寿命直接測定のための PbF2 カロリメータの性能評価 (2)」, 日本物理学会 2020 年秋季大会, オンライ
ン, 2021 年 3 月 12–15 日.
山我拓巳 （招待講演）, “Measurement of spin-spin correlation in K − pp decay,” 日本のスピン物理学の展望, オンライン, 2021 年 2 月
23–24 日.
山我拓巳 （招待講演）, 「J-PARC E15 実験における KNN 束縛状態の発見と今後の展望」, ELPH 研究会 C029「様々なフレーバー領域で探るクォーク・ハドロン多体系の分光と構造」, 宮城県仙台市 (東北大学電子光理学研究センター), 2020 年 11 月 4–5 日.

Press Releases
正負のミュオンで捉えたイオンの動き 2020 年 8 月 7 日—Li イオンの動きを, 負ミュオンで確認, 正ミュオンで詳細観察—一般財
団法人総合科学研究機構（CROSS）中性子科学センター杉山 純サイエンスコーディネータ国立研究開発法人理化学研究所（理研）仁科加速器科学研究センター石田勝彦協力研究員.

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