H. Ekawa

activity

20142025

most citedObservation of Spin-Dependent Charge Symmetry Breaking in

Λ N

Interaction: Gamma-Ray Spectroscopy of

_{Λ}^{4}

115 citations · 388 across the 20 of their papers we have counts for

collaborators

21 papers

nucl-ex2025

Excitation Spectra of the $^{12} C (p, d)$ Reaction near the $η^{'}$ -Meson Emission Threshold Measured in Coincidence with High-Momentum Protons

R. Sekiya, K. Itahashi, Y. K. Tanaka +74

The missing mass of the $^{12} C (p, d)$ reaction has been measured near the $η^{'}$ -meson emission threshold in coincidence with a high-momentum proton to selectively collect $η…

physics.ins-det2025

Performance of newly constructed plastic scintillator barrel in the WASA-FRS experiments and evaluation of radiation damage effects on multi-pixel photon counter

Y. K. Tanaka, R. Sekiya, K. Itahashi +70

A barrel-shaped plastic scintillation counter with Multi-Pixel Photon Counter (MPPC) readout has been developed and operated in the first WASA-FRS experimental campaign at GSI. The…

nucl-ex2025

Measurement of $Λ$ Polarization in the $π^{-} p \to K^{0} Λ$ Reaction at $p_{π^{-}} = 1.33$ GeV/ $c$ toward a New $Λ p$ Scattering Experiment

PARC E40 Collaboration, T. Sakao, K. Miwa +69

This paper presents high-precision experimental data of the polarization of the $Λ$ hyperon in the $π^{-} p \to K^{0} Λ$ reaction, measured in the angular range $0.6<\cos θ^{CM}_{K0…

nucl-ex2025

Artificial intelligence pioneers the double-strangeness factory

Yan He, Takehiko R. Saito, Hiroyuki Ekawa +11

Artificial intelligence (AI) is transforming not only our daily experiences but also the technological development landscape and scientific research. In this study, we pioneered th…

nucl-ex2025★ 6 cited

Binding energy of $_{Λ}^{3} H$ and $_{Λ}^{4} H$ via image analyses of nuclear emulsions using deep-learning

Ayumi Kasagi, Takehiko R. Saito, Vasyl Drozd +16

Subatomic systems are pivotal for understanding fundamental baryonic interactions, as they provide direct access to quark-level degrees of freedom. In particular, introducing a str…

hep-ex2024

A novel machine learning method to detect double- $Λ$ hypernuclear events in nuclear emulsions

Yan He, Vasyl Drozd, Hiroyuki Ekawa +17

A novel method was developed to detect double- $Λ$ hypernuclear events in nuclear emulsions using machine learning techniques. The object detection model, the Mask R-CNN, was traine…

nucl-ex2023★ 6 cited

Hypernuclear event detection in the nuclear emulsion with Monte Carlo simulation and machine learning

A. Kasagi, W. Dou, V. Drozd +18

This study developed a novel method for detecting hypernuclear events recorded in nuclear emulsion sheets using machine learning techniques. The artificial neural network-based obj…

physics.ins-det2022★ 6 cited

Study on the reusability of fluorescent nuclear track detectors using optical bleaching

Abdul Muneem, Junya Yoshida, Hiroyuki Ekawa +14

Fluorescent nuclear track detectors (FNTDs) based on Al $_{2}$ O $_{3}$ :C,Mg crystals are luminescent detectors that can be used for dosimetry and detection of charged particles and n…

physics.ins-det2022★ 1 cited

Investigation of the neutron imaging applications using fine-grained nuclear emulsion

Abdul Muneem, Junya Yoshida, Hiroyuki Ekawa +11

Neutron imaging is a non-destructive inspection technique with a wide range of applications. One of the important aspects concerning neutron imaging is achieving micrometer-scale s…

nucl-ex2022

Measurement of differential cross sections for $Σ^{+} p$ elastic scattering in the momentum range 0.44-0.80 GeV/c

PARC E40 Collaboration, T. Nanamura, K. Miwa +69

We performed a novel $Σ^{+} p$ scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 $Σ^{+} p$ elastic scattering events were identified from $4.9 \times…

nucl-ex2021★ 2 cited

Precise measurement of differential cross sections of the Σ-p --> Λ n reaction in momentum range 470-650 MeV/c

PARC E40 Collaboration, K. Miwa, J. K. Ahn +69

The differential cross sections of the Σ-p --> Λ n reaction were measured accurately for the Σ- momentum (p_{Σ}) ranging from 470 to 650 MeV/c at the J-PARC Hadron Experimental Fac…

nucl-ex2021★ 18 cited

Novel method for producing very-neutron-rich hypernuclei via charge-exchange reactions with heavy ion projectiles

Takehiko Saito, Hiroyuki Ekawa, Manami Nakagawa

We propose a novel method for producing very-neutron-rich hypernuclei and corresponding resonance states by employing charge-exchange reactions via pp( $^{12}$ C, $^{12}$ N $K^{+}$ )n $Λ$ …

nucl-ex2021★ 1 cited

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

PARC E40 Collaboration, K. Miwa, J. K. Ahn +69

A high statistics $Σ p$ scattering experiment has been performed at the J-PARC Hadron Experimental Facility. Data for momentum-tagged $Σ^{-}$ running in a liquid hydrogen target wer…

nucl-ex2021★ 51 cited

First observation of a nuclear $s$ -state of $Ξ$ hypernucleus, $_{Ξ}^{15} C$

M. Yoshimoto, J. K. Ahn, B. Bassalleck +46

Bound-systems of $Ξ^{-}$ -- $_{14} N$ are studied via $Ξ^{-}$ capture at rest followed by emission of a twin single- $Λ$ hypernucleus in the emulsion detectors. Two events forming…

nucl-ex2020★ 12 cited

CNN-based event classification for alpha-decay events in nuclear emulsion

J. Yoshida, H. Ekawa, A. Kasagi +6

We developed an efficient classifier that sorts alpha-decay events from various vertex-like objects in nuclear emulsion using a convolutional neural network (CNN). Alpha-decay even…

nucl-ex2018★ 55 cited

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

H. Ekawa, K. Agari, J. K. Ahn +100

A double- $Λ$ hypernucleus, $_{ΛΛ} Be$ , was observed by the J-PARC E07 collaboration in nuclear emulsions tagged by the $(K^{-}, K^{+})$ reaction. This event was interprete…

nucl-ex2017★ 19 cited

First Determination of Level Structure of an $s d$ -Shell Hypernucleus, $_{Λ}^{19} F$

S. B. Yang, J. K. Ahn, Y. Akazawa +45

We report on the first observation of $γ$ rays emitted from an $s d$ -shell hypernucleus, $_{Λ}^{19} F$ . The energy spacing between the ground state doublet, $1/ 2^{+}$ and $3/ 2^{+}$ …

nucl-ex2016★ 2 cited

Search for Pentaquark Theta+ in Hadronic Reaction at J-PARC

M. Naruki

A variety of nuclear and hadron physics experiments are being performed using meson beams at the J-PARC Hadron Facility. As the first experiment at the facility, the pentaquark The…

nucl-ex2015★ 115 cited

Observation of Spin-Dependent Charge Symmetry Breaking in $Λ N$ Interaction: Gamma-Ray Spectroscopy of $_{Λ}^{4}$ He

T. O. Yamamoto, M. Agnello, Y. Akazawa +51

The energy spacing between the ground-state spin doublet of $_{Λ}^{4}$ He(1 $^{+}$ ,0 $^{+}$ ) was determined to be $1406 \pm 2 \pm 2$ keV, by measuring $γ$ rays for the $1^{+} \to 0^{+}$ transitio…

nucl-ex2014★ 71 cited

Observation of the " $K^{-} pp$ "-like structure in the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/ $c$

Yudai Ichikawa, Tomofumi Nagae, Hiroyuki Fujioka +41

We have observed a " $K^{-} pp$ "-like structure in the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/ $c$ . In this reaction $Λ (1405)$ hyperon resonance is expected to be produced as a doorway to fo…

nucl-ex2014★ 23 cited

Inclusive spectrum of the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/c

Yudai Ichikawa, Tomofumi Nagae, Hyoungchan Bhang +41

We have measured an inclusive missing-mass spectrum of the $d (π^{+}, K^{+})$ reaction at the pion incident momentum of 1.69 GeV/ $c$ at the laboratory scattering angles between 2$^\circ…

Excitation Spectra of the 12C(p,d) Reaction near the η′-Meson Emission Threshold Measured in Coincidence with High-Momentum Protons

Performance of newly constructed plastic scintillator barrel in the WASA-FRS experiments and evaluation of radiation damage effects on multi-pixel photon counter

Measurement of Λ Polarization in the π−p→K0Λ Reaction at pπ−​=1.33 GeV/c toward a New Λp Scattering Experiment

Artificial intelligence pioneers the double-strangeness factory

Binding energy of Λ3​H and Λ4​H via image analyses of nuclear emulsions using deep-learning

A novel machine learning method to detect double-Λ hypernuclear events in nuclear emulsions

Hypernuclear event detection in the nuclear emulsion with Monte Carlo simulation and machine learning

Study on the reusability of fluorescent nuclear track detectors using optical bleaching

Investigation of the neutron imaging applications using fine-grained nuclear emulsion

Measurement of differential cross sections for Σ+p elastic scattering in the momentum range 0.44-0.80 GeV/c

Precise measurement of differential cross sections of the Σ-p --> Λ n reaction in momentum range 470-650 MeV/c

Novel method for producing very-neutron-rich hypernuclei via charge-exchange reactions with heavy ion projectiles

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

First observation of a nuclear s-state of Ξ hypernucleus, Ξ15​C

CNN-based event classification for alpha-decay events in nuclear emulsion

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

First Determination of Level Structure of an sd-Shell Hypernucleus, Λ19​F

Search for Pentaquark Theta+ in Hadronic Reaction at J-PARC

Observation of Spin-Dependent Charge Symmetry Breaking in ΛN Interaction: Gamma-Ray Spectroscopy of Λ4​He

Observation of the "K−pp"-like structure in the d(π+,K+) reaction at 1.69 GeV/c

Inclusive spectrum of the d(π+,K+) reaction at 1.69 GeV/c

Excitation Spectra of the $^{12} C (p, d)$ Reaction near the $η^{'}$ -Meson Emission Threshold Measured in Coincidence with High-Momentum Protons

Measurement of $Λ$ Polarization in the $π^{-} p \to K^{0} Λ$ Reaction at $p_{π^{-}} = 1.33$ GeV/ $c$ toward a New $Λ p$ Scattering Experiment

Binding energy of $_{Λ}^{3} H$ and $_{Λ}^{4} H$ via image analyses of nuclear emulsions using deep-learning

A novel machine learning method to detect double- $Λ$ hypernuclear events in nuclear emulsions

Measurement of differential cross sections for $Σ^{+} p$ elastic scattering in the momentum range 0.44-0.80 GeV/c

First observation of a nuclear $s$ -state of $Ξ$ hypernucleus, $_{Ξ}^{15} C$

First Determination of Level Structure of an $s d$ -Shell Hypernucleus, $_{Λ}^{19} F$

Observation of Spin-Dependent Charge Symmetry Breaking in $Λ N$ Interaction: Gamma-Ray Spectroscopy of $_{Λ}^{4}$ He

Observation of the " $K^{-} pp$ "-like structure in the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/ $c$

Inclusive spectrum of the $d (π^{+}, K^{+})$ reaction at 1.69 GeV/c