H. Nanjo
YOU?
Author Swipe
View article: Experimental Verification of a Convolutional Neural Network Separation Method in TeV Gamma-Ray Observations by the Tibet ASγ Experiment
Experimental Verification of a Convolutional Neural Network Separation Method in TeV Gamma-Ray Observations by the Tibet ASγ Experiment Open
Since 1990, the Tibet AS$\gamma$ experiment has been observing gamma rays and cosmic rays with energies greater than several TeV using a surface air shower array. An underground muon detector (MD) array operating since 2014 enables us to s…
View article: Kaon physics: a cornerstone for future discoveries
Kaon physics: a cornerstone for future discoveries Open
The kaon physics programme, long heralded as a cutting-edge frontier by the European Strategy for Particle Physics, continues to stand at the intersection of discovery and innovation in high-energy physics (HEP). With its unparalleled capa…
View article: Search for the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>K</mml:mi></mml:mrow><mml:mrow><mml:mi>L</mml:mi></mml:mrow></mml:msub><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup><mml:mi>ν</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi>ν</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover></mml:mrow></mml:math> Decay at the J-PARC KOTO Experiment
Search for the Decay at the J-PARC KOTO Experiment Open
We performed a search for the KL→π0νν¯ decay using the data taken in 2021 at the J-PARC KOTO experiment. With newly installed counters and new analysis method, the expected background was suppressed to 0.252±0.055stat −0.067syst+0.052. Wit…
View article: Proposal of the KOTO II experiment
Proposal of the KOTO II experiment Open
International audience
View article: KOTO II at J-PARC to measure the branching ratio of $K_L\to \pi^0\nu\overline{\nu}$
KOTO II at J-PARC to measure the branching ratio of $K_L\to \pi^0\nu\overline{\nu}$ Open
The KOTO II is a next-generation experiment to measure the branching ratio of $K_L\\to \\pi^0\\nu\\bar{\\nu}$ with 30-GeV proton beam at J-PARC. The KOTO II is a successor of the currently running KOTO experiment. We plan to expand the had…
View article: Mini-Proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024)"
Mini-Proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024)" Open
The mini proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024) [https://kds.kek.jp/event/46965]" held at J-PARC, February 19-21, 2024, are presented. The worksh…
View article: Measurement of muon flux behind the beam dump of the J-PARC Hadron Experimental Facility
Measurement of muon flux behind the beam dump of the J-PARC Hadron Experimental Facility Open
A muon-flux measurement behind the beam dump of the J-PARC Hadron Experimental Facility was performed with a compact muon detector that can be inserted into a vertical observing hole with 81 mm in diameter which was dug underground. The de…
View article: Workshop summary: Kaons@CERN 2023
Workshop summary: Kaons@CERN 2023 Open
View article: Modeling of TeV Galactic Cosmic-ray Anisotropy based on Intensity Mapping in an MHD Model Heliosphere
Modeling of TeV Galactic Cosmic-ray Anisotropy based on Intensity Mapping in an MHD Model Heliosphere Open
Cosmic rays do not arrive at the Earth uniformly. Recent experiments have consistently observed small anisotropies with amplitudes of ∼0.2% in the arrival directions of cosmic rays at TeV energies. We perform the modeling of the cosmic-ray…
View article: Status of the KOTO experiment to search for kaon rare decays
Status of the KOTO experiment to search for kaon rare decays Open
The $K_L\to\pi^0\nu\overline{\nu}$ decay is searched for in the KOTO experiment. In the analysis of 2016-2018 data, we found new background sources, a charged kaon decay and a beam-halo $K_L$ decay. In the analysis of 2020 data, we show th…
View article: Suppression of neutron background using deep neural network and Fourier frequency analysis at the KOTO experiment
Suppression of neutron background using deep neural network and Fourier frequency analysis at the KOTO experiment Open
View article: Workshop summary -- Kaons@CERN 2023
Workshop summary -- Kaons@CERN 2023 Open
Kaon physics is at a turning point -- while the rare-kaon experiments NA62 and KOTO are in full swing, the end of their lifetime is approaching and the future experimental landscape needs to be defined. With HIKE, KOTO-II and LHCb-Phase-II…
View article: Suppression of Neutron Background using Deep Neural Network and Fourier Frequency Analysis at the KOTO Experiment
Suppression of Neutron Background using Deep Neural Network and Fourier Frequency Analysis at the KOTO Experiment Open
We present two analysis techniques for distinguishing background events induced by neutrons from photon signal events in the search for the rare $K^0_L\rightarrowπ^0ν\barν$ decay at the J-PARC KOTO experiment. These techniques employed a d…
View article: Observation of Gamma Rays up to 320 TeV from the Middle-aged TeV Pulsar Wind Nebula HESS J1849−000
Observation of Gamma Rays up to 320 TeV from the Middle-aged TeV Pulsar Wind Nebula HESS J1849−000 Open
Gamma rays from HESS J1849−000, a middle-aged TeV pulsar wind nebula (PWN), are observed by the Tibet air shower array and the muon detector array. The detection significance of gamma rays reaches 4.0 σ and 4.4 σ levels above 25 TeV and 10…
View article: Observation of gamma rays up to 320 TeV from the middle-aged TeV pulsar wind nebula HESS J1849$-$000
Observation of gamma rays up to 320 TeV from the middle-aged TeV pulsar wind nebula HESS J1849$-$000 Open
Gamma rays from HESS J1849$-$000, a middle-aged TeV pulsar wind nebula (PWN), are observed by the Tibet air shower array and the muon detector array. The detection significance of gamma rays reaches $4.0\, σ$ and $4.4\, σ$ levels above 25 …
View article: Observation of gamma rays from the northern celestial sky up to the sub-PeV range with the Tibet air shower array and its underground muon detector array
Observation of gamma rays from the northern celestial sky up to the sub-PeV range with the Tibet air shower array and its underground muon detector array Open
Gamma-ray observation in the sub-PeV range helps us search for Galactic PeV cosmic-ray accelerators, PeVatrons. Measurement of the energy spectrum of gamma rays from astrophysical sources is especially crucial to discuss their hadronic or …
View article: Search for the Pair Production of Dark Particles <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi></mml:math> with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>K</mml:mi><mml:mi>L</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo stretchy="false">→</mml:mo><mml:mi>X</mml:mi><mml:mi>X</mml:mi></mml:math>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>γ</mml:mi><mml:mi>γ</mml:mi></mml:math>
Search for the Pair Production of Dark Particles with , Open
We present the first search for the pair production of dark particles X via K_{L}^{0}→XX with X decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40-110 MeV/c^{2} and 210…
View article: KOTO II at J-PARC : toward measurement of the branching ratio of KL→π0νν¯
KOTO II at J-PARC : toward measurement of the branching ratio of KL→π0νν¯ Open
The KOTO II experiment at J-PARC is a next-generation experiment that is under design aiming at the measurement of the branching ratio of the decay. The KOTO II experiment is planned in the extended Hadron Experimental Facility…
View article: New physics searches at kaon and hyperon factories
New physics searches at kaon and hyperon factories Open
Rare meson decays are among the most sensitive probes of both heavy and light new physics. Among them, new physics searches using kaons benefit from their small total decay widths and the availability of very large datasets. On the other h…
View article: Search for the Pair Production of Dark Particles $X$ with $K_L^0 \to XX$, $X \to γγ$
Search for the Pair Production of Dark Particles $X$ with $K_L^0 \to XX$, $X \to γγ$ Open
We present the first search for the pair production of dark particles $X$ via $K_L^0\to XX$ with $X$ decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40 - 110 MeV/c$^2$ …
View article: Measurement of the Gamma-Ray Energy Spectrum beyond 100 TeV from the HESS J1843–033 Region
Measurement of the Gamma-Ray Energy Spectrum beyond 100 TeV from the HESS J1843–033 Region Open
HESS J1843–033 is a very high energy gamma-ray source whose origin remains unidentified. This work presents, for the first time, the energy spectrum of gamma rays beyond 100 TeV from the HESS J1843–033 region using the data recorded by the…
View article: Japan's Strategy for Future Projects in High Energy Physics
Japan's Strategy for Future Projects in High Energy Physics Open
The current strategy for future projects of the Japanese high energy physics community, Japan Association of High Energy Physicists (JAHEP), remains as described in the Final Report of the Committee on Future Projects in High Energy Physic…
View article: J-PARC hadron experimental facility extension project *
J-PARC hadron experimental facility extension project * Open
The J-PARC Hadron Experimental Facility was constructed with an aim to explore the origin and evolution of matter in the universe through experiments with intense particle beams. In the past decade, many results from particle and nuclear p…
View article: Extension of the J-PARC Hadron Experimental Facility: Third White Paper
Extension of the J-PARC Hadron Experimental Facility: Third White Paper Open
The J-PARC Hadron Experimental Facility was constructed with an aim to explore the origin and evolution of matter in the universe through the experiments with intense particle beams. In the past decade, many results on particle and nuclear…
View article: Gamma-Ray Observation of the Cygnus Region in the 100-TeV Energy Region
Gamma-Ray Observation of the Cygnus Region in the 100-TeV Energy Region Open
We report observations of gamma-ray emissions with energies in the 100-TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their …
View article: First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies
First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies Open
We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources an…
View article: Study of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>K</mml:mi><mml:mi>L</mml:mi></mml:msub><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>π</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mi>ν</mml:mi><mml:mover accent="true"><mml:mi>ν</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:math> Decay at the J-PARC KOTO Experiment
Study of the Decay at the J-PARC KOTO Experiment Open
The rare decay K_{L}→π^{0}νν[over ¯] was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of (7.20±0.05_{stat}±0.66_{syst})×10^{-10}, three candidate events were observed…
View article: Pulse shape discrimination of photons and neutrons in the energy range of 0.1 – 2 GeV with the KOTO un-doped CsI calorimeter
Pulse shape discrimination of photons and neutrons in the energy range of 0.1 – 2 GeV with the KOTO un-doped CsI calorimeter Open
View article: First search for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>K</mml:mi><mml:mi>L</mml:mi></mml:msub><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>π</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mi>γ</mml:mi></mml:math>
First search for Open
We report the first search for the $K_L \\to \\pi^0 \\gamma$ decay, which is\nforbidden by Lorentz invariance, using the data from 2016 to 2018 at the J-PARC\nKOTO experiment. With a single event sensitivity of $(7.1\\pm 0.3_{\\rm stat.}\n…
View article: CsI calorimeter for the J-PARC KOTO experiment
CsI calorimeter for the J-PARC KOTO experiment Open