14 results on '"Sagawa, Hiroyuki"'
Search Results
2. The JEM-EUSO Program for UHECR Studies from Space
- Author
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Parizot Etienne, Casolino Marco, Picozza Piergiorgio, Ebisuzaki Toshikazu, Bertaina Mario Edoardo, Fuglesang Christer, Haungs Andreas, Kajino Fumiyoshi, Klimov Pavel, Olinto Angela, Ricci Marco, Sagawa Hiroyuki, Szabelski Jacek, and Wiencke Lawrence
- Subjects
Physics ,QC1-999 - Abstract
To take up the challenge of understanding the origin of the ultra-high-energy cosmic rays (UHECRs), new observational means appear necessary. The JEM-EUSO Collaboration has undertaken to open the space road to UHECR studies. For more than a decade, it has been developing a realistic program to measure the UHECRs from space with unprecedented aperture, together with complementary scientific objectives in a broader multidisciplinary context. Several intermediate missions have already been completed (on the ground: EUSO-TA; under stratospheric ballons: EUSO-Balloon and EUSO-SPB1; in space: TUS, and on-board the ISS: MINI-EUSO), and others are in preparation for flight (EUSO-SPB2), under review (K-EUSO: currently on hold), or proposed for the next decade (POEMMA). We report on the general status of the JEM-EUSO program, underlining that its technology has now reached operational maturity, and is ready for actual cosmic-ray shower detection from above.
- Published
- 2023
- Full Text
- View/download PDF
3. A Bayesian source association analysis of UHECRs: Impact of the Galactic magnetic field and composition
- Author
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Watanabe Keito, Fedynitch Anatoli, Capel Francesca, and Sagawa Hiroyuki
- Subjects
Physics ,QC1-999 - Abstract
We present a statistical analysis of the association between UHECRs and proposed astrophysical sources. Our approach is based on the Bayesian hierarchical framework presented in Capel & Mortlock 2019, but with notable extensions. Using CRPropa3, we now include the lensing effect of the Galactic magnetic field and explore the impact of heavier compositions. This analysis directly connects to the physics of UHECR propagation so that each detected event is allowed different possible deflections and energy-loss horizons based on its measured energy, arrival direction and the corresponding uncertainties. In this way, we can easily interpret the connection to proposed sources in a physical way. We verify our approach using simulated data and then present our results with views of the Northern and Southern skies thanks to publicly available data from both the Telescope Array experiment and Pierre Auger Observatory.
- Published
- 2023
- Full Text
- View/download PDF
4. Auger@TA: Deploying an independent Pierre Auger Observatory SD micro-array at the Telescope Array Project
- Author
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Mayotte Sonja, Caraça-Valente Jorge, Covault Corbin, Fujii Toshihiro, Im Sungrae, James Robin, Johnsen Jeffrey, Kampert Karl-Heinz, Kern Heiko, Matthews John, Mayotte Eric, Bartz Mocellin Adriel, Quinn Sean, Rautenberg Julian, Roth Markus, Sagawa Hiroyuki, Sako Takashi, Sarazin Frederic, Sato Ricardo, Schmidt David, Thomas Stan, and Wörner Günther
- Subjects
Physics ,QC1-999 - Abstract
The Pierre Auger Observatory (Auger) and the Telescope Array Project (TA) are the two largest ultra-high-energy cosmic ray observatories in the world. They operate in the Southern and Northern hemispheres, respectively, at similar latitudes but with different surface detector (SD) designs. This difference in detector design changes their sensitivity to the various components of extensive air showers. The over-arching goal of the Auger@TA working group is to cross-calibrate the SD arrays of the two observatories in order to identify or rule out systematic causes for the apparent differences in the flux measured at Auger and TA. The project itself is divided into two phases. Phase-I finished in 2020 and consisted of a station-level comparison facilitated by the deployment of two Auger stations, one prototype station with a single central PMT and a standard Auger station, in the middle of the TA SD near the Central Laser Facility, along with a modified TA station to provide external triggers from the TA SD. This provided the opportunity to observe the same extensive air showers with both Auger and TA detectors to directly compare their measurements. Phase-II of Auger@TA is currently underway and aims at building a self-triggering micro-Auger-array inside the TA array. This micro-array consists of eight Auger stations, seven of which use a 1-PMT prototype configuration and form a single hexagon with a traditional 1.5 km Auger spacing. The 8th station is of the standard Auger 3-PMT configuration and is placed at the center of the hexagon, along with a TA station to form a triplet. Each Auger station will also be outfitted with an AugerPrime Surface Scintillator Detector. A custom communication system using readily available components will be used to provide communication between the stations and remote access to each station via a central communications station. The deployment of the micro-array took place at the end of September 2022. A simulation study was carried out to gauge the expected performance of the Auger@TA micro-array and to derive trigger effi ciencies and event rates.
- Published
- 2023
- Full Text
- View/download PDF
5. The Auger@TA Project: Phase II Progress and Plans
- Author
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Covault Corbin, Fujii Toshihiro, Halliday Robert, Johnsen Jeffrey, Lorek Ryan, Nonaka Toshiyuki, Quinn Sean, Sagawa Hiroyuki, Sako Takashi, Sarazin Fred, Sato Ricardo, Schmidt David, and Takeishi Ryuji
- Subjects
Physics ,QC1-999 - Abstract
The Auger@TA project is a combined effort involving members of both the Pierre Auger Observatory and the Telescope Array experiment (TA) to cross-calibrate detectors and compare results on air showers detected at one location. We have recently reported results from Phase I of the project, during which we collected and presented data from two Auger water Cherenkov surface detector stations deployed into the TA experiment near the Central Laser Facility. For Phase II, we will deploy a micro-array of six or seven single-PMT Auger surface detector stations co-located with TA scintillator surface detector stations. The Auger micro-array will trigger and collect data independently from the TA allowing for a complete end-to-end comparison of detector data, calibration, and reconstructed event quantities on a shower-by-shower basis between the TA and Auger detector systems. We describe progress towards development of the micro-array for Phase II including the preparation of surface detector water tanks, station electronics, wireless communications, triggers, and data acquisition. We also outline plans for deploying the Auger@TA micro-array into the TA experiment in 2019 with preliminary estimates for coincident air-shower rates.
- Published
- 2019
- Full Text
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6. Single and Double Charge Exchange Excitations of Spin-Isospin Mode
- Author
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Sagawa Hiroyuki
- Subjects
Physics ,QC1-999 - Abstract
We study the sum rules of double Gamow-Teller (DGT) excitations through double spin-isospin operator (σt)2 In general, 2+states in the granddaughter nuclei have dominant transition strength in DGT excitations and 0+states are weak, except in T = 1 mother nuclei in which 0+strength is competitive with 2+strength. A possibility to extract the unit cross section for the DGT transition strength is pointed out in the (#x03C3;t)2 excitation of double isobaric analog state (DIAS) in T = 1 nuclei.
- Published
- 2019
- Full Text
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7. Observation of radio emissions from electron beams using an ice target
- Author
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Mase Keiichi, Ikeda Daisuke, Ishihara Aya, Sagawa Hiroyuki, Shibata Tatsunobu, Fukushima Masaki, Yamamoto Tokonatsu, Yoshida Shigeru, Gaïor Romain, Hanson Kael, Matthews John N., Meures Thomas, Shin Bokkyun, Thomson Gordon, and de Vries Krijn
- Subjects
Physics ,QC1-999 - Abstract
To observe high energy cosmogenic neutrinos above 50 PeV, the large neutrino telescope ARA is being built at the South Pole. The ARA telescope detects neutrinos by observing radio signals by the Askaryan effect. We performed an experiment using 40 MeV electron beams of the Telescope Array Electron Light Source to verify the understanding of the Askaryan emission as well as the detector responses used in the ARA experiment. Clear coherent polarized radio signals were observed with and without an ice target. We found that the observed radio signals are consistent with simulation, showing that our understanding of the radio emissions and the detector responses are within the systematic uncertainties of the ARAcalTA experiment which is at the level of 30%.
- Published
- 2019
- Full Text
- View/download PDF
8. Overview of the Auger@TA project and preliminary results from Phase I
- Author
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Sarazin Fred, Covault Corbin, Fujii Toshihiro, Halliday Robert, Johnsen Jeffrey, Lorek Ryan, Nonaka Toshiyuki, Quinn Sean, Sagawa Hiroyuki, Sako Takashi, Sato Ricardo, Schmidt David, and Takeishi Ryuji
- Subjects
Physics ,QC1-999 - Abstract
We report on the first results of a unique in-situ experimental cross-calibration effort of the surface detector of the Pierre Auger Observatory and of the Telescope Array experiment (Auger@TA). In the first phase of Auger@TA, we performed surface detector station-to-station comparisons for a collection of extensive air showers landing near the experimental setup and detected by Telescope Array. Beyond the deduced cross-calibration curve between the Water-Cherenkov-based Auger and Scintillator-based TA Surface Detector stations, we also investigate the consistency of their response for individual reconstructed showers. The dataset is currently too small to draw firm conclusions as-of-yet. Hence, phase I data taking will continue even as we gear up for the deployment of an Auger micro-array within Telescope Array as part of Phase II of this work.
- Published
- 2019
- Full Text
- View/download PDF
9. Isoscalar and isovector spin responses in p-shell and sd-shell nuclei
- Author
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Sagawa Hiroyuki and Suzuki Toshio
- Subjects
Physics ,QC1-999 - Abstract
We study the spin magnetic dipole transitions in sd-shell even-even nuclei with N=Z and a p-shell nucleus 12C by modern shell model calculations. The shell model wave functions take into account enhanced isoscalar (IS) spin-triplet pairing as well as the effective spin operators. We point out that the IS pairing and the effective spin operators give a large quenching effect on the isovector (IV) spin transitions to be consistent with observed data by (p, p′) experiments. On the other hand, the observed IS spin strengths do not show large quenching effect suggested by the calculated investigation. The IS pairing gives a substantial quenching effect on the spin magnetic dipole transitions, especially on the IV ones.
- Published
- 2018
- Full Text
- View/download PDF
10. Search for molecular bremsstrahlung radiation signals in Ku band with coincidental operations of radio telescopes with air shower detectors
- Author
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Fukushima Masaki, Sakurai Nobuyuki, Fujii Toshihiro, Akimune Hidetoshi, Iijima Takashi, Kuramoto Kazuyuki, Yamamoto Tokonatsu, Ogio Shoichi, and Sagawa Hiroyuki
- Subjects
Physics ,QC1-999 - Abstract
Microwave radiation from extensive air showers is expected to provide a new technique to observe UHECR. We insatlled and operate radio telescopes in Osaka and at Telescope Array site in Utah, USA. In Osaka, we are coincidentally operating two Ku band radio telescopes with an air shower array which consists of nine plastic scintillators with about 10 m separation. In Utah, we installed two telescopes just beside the Black Rock Mesa fluorescence detector (FD) station of the Telescope Array experiment, and we operated the radio telescopes coincidentally with FD event triggers. We report the experimental setups and the results of these measurements.
- Published
- 2013
- Full Text
- View/download PDF
11. Single and Double Charge Exchange Excitations of Spin-Isospin Mode.
- Author
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de Angelis, G., Corradi, L., and Sagawa, Hiroyuki
- Subjects
ISOBARIC spin ,SUM rules (Physics) ,TRANSITION strengths ,NUCLEAR excitation ,NUCLEAR structure - Abstract
We study the sum rules of double Gamow-Teller (DGT) excitations through double spin-isospin operator (σt
- )2 In general, 2+ states in the granddaughter nuclei have dominant transition strength in DGT excitations and 0+ states are weak, except in T = 1 mother nuclei in which 0+ strength is competitive with 2+ strength. A possibility to extract the unit cross section for the DGT transition strength is pointed out in the (#x03C3;t- )2 excitation of double isobaric analog state (DIAS) in T = 1 nuclei. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
12. Isoscalar and isovector spin responses in p-shell and sd-shell nuclei.
- Author
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Arsenyev, N., Bezbakh, A., Rogov, I., Shneidman, T., Vdovin, A., Sagawa, Hiroyuki, and Suzuki, Toshio
- Subjects
SPIN magnetic resonance ,NEUTRINOLESS double beta decay ,NUCLEAR resonance reactions ,NUCLEAR structure ,NUCLEAR shell theory - Abstract
We study the spin magnetic dipole transitions in sd-shell even-even nuclei with N=Z and a p-shell nucleus
12 C by modern shell model calculations. The shell model wave functions take into account enhanced isoscalar (IS) spin-triplet pairing as well as the effective spin operators. We point out that the IS pairing and the effective spin operators give a large quenching effect on the isovector (IV) spin transitions to be consistent with observed data by (p, p′) experiments. On the other hand, the observed IS spin strengths do not show large quenching effect suggested by the calculated investigation. The IS pairing gives a substantial quenching effect on the spin magnetic dipole transitions, especially on the IV ones. [ABSTRACT FROM AUTHOR]- Published
- 2018
13. Observation of radio emissions from electron beams using an ice target.
- Author
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Riccobene, G., Biagi, S., Capone, A., Distefano, C., Piattelli, P., Mase, Keiichi, Ikeda, Daisuke, Ishihara, Aya, Sagawa, Hiroyuki, Shibata, Tatsunobu, Fukushima, Masaki, Yamamoto, Tokonatsu, Yoshida, Shigeru, Gaïor, Romain, Hanson, Kael, Matthews, John N., Meures, Thomas, Shin, Bokkyun, Thomson, Gordon, and de Vries, Krijn
- Subjects
NEUTRINO detectors ,ULTRA-high energy cosmic rays ,RADIO antennas ,COSMIC ray showers - Abstract
To observe high energy cosmogenic neutrinos above 50 PeV, the large neutrino telescope ARA is being built at the South Pole. The ARA telescope detects neutrinos by observing radio signals by the Askaryan effect. We performed an experiment using 40 MeV electron beams of the Telescope Array Electron Light Source to verify the understanding of the Askaryan emission as well as the detector responses used in the ARA experiment. Clear coherent polarized radio signals were observed with and without an ice target. We found that the observed radio signals are consistent with simulation, showing that our understanding of the radio emissions and the detector responses are within the systematic uncertainties of the ARAcalTA experiment which is at the level of 30%. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. Search for molecular bremsstrahlung radiation signals in Ku band with coincidental operations of radio telescopes with air shower detectors
- Author
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Ogio, Shoichi, primary, Yamamoto, Tokonatsu, additional, Kuramoto, Kazuyuki, additional, Iijima, Takashi, additional, Akimune, Hidetoshi, additional, Fujii, Toshihiro, additional, Sakurai, Nobuyuki, additional, Fukushima, Masaki, additional, and Sagawa, Hiroyuki, additional
- Published
- 2013
- Full Text
- View/download PDF
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