T. Seki

Shinshu University

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M. Tanaka

High Energy Accelerator Research Organization

P. Križan

University of Ljubljana

T. Sumiyoshi

Kyoto University

T. Shibata

The University of Tokyo

Y. Tameda

Osaka Electro-Communication University

I. Adachi

High Energy Accelerator Research Organization

O. Kalashev

Institute for Nuclear Research

Jon Paul Lundquist

University of Nova Gorica

Y. Tsunesada

Osaka Metropolitan University

M. Kuznetsov

Institute for Nuclear Research

Cooperative Institutions

Consejo Nacional de Investigaciones Científicas y Técnicas

531

Laboratoire d’Annecy de Physique des Particules

516

Instituto de Tecnologías en Detección y Astropartículas

447

Centre National de la Recherche Scientifique

441

University of Buenos Aires

428

Universidad Nacional de La Plata

421

The University of Tokyo

419

Campbell Collaboration

413

National University of General San Martín

390

Pierre Auger Observatory

379

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Joint analysis of the energy spectrum of ultra-high-energy cosmic rays as measured at the Pierre Auger Observatory and the Telescope Array

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2021)

Y. Tsunesada Rasha Abbasi T. Abu‐Zayyad Monica Allen Yuto Arai

The measurement of the energy spectrum of ultra-high-energy cosmic rays (UHECRs) is of crucial importance to clarify their origin and acceleration mechanisms. The Pierre Auger Observatory in Argentina and the Telescope Array (TA) in the US have reported their measurements of UHECR energy spectra observed in the southern and northern hemisphere, respectively. The region of the sky accessible to both Observatories ($[-15,+24]$ degrees in declination) can be used to cross-calibrate the two spectra. The Auger-TA energy spectrum working group was organized in 2012 and has been working to understand the uncertainties in energy scale in both experiments, their systematic differences, and differences in the shape of the spectra. In previous works, we reported that there was an overall agreement of the energy spectra measured by the two observatories below 10 EeV while at higher energies, a remaining significant difference was observed in the common declination band. We revisit this issue to understand its origin by examining the systematic uncertainties, statistical effects, and other possibilities. We will also discuss the differences in the spectra in different declination bands and a new feature in the spectrum recently reported by the Auger Collaboration.

Pierre Auger Observatory

Right ascension

10.22323/1.395.0337

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Citations (27)

Observation of B+ ---> K(1)(1270)+ gamma

Contributed to (2004)

Kazuo Abe Heyoung Yang Y. Chao D. Žontar D. Liventsev

Source

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Citations (0)

Study of a proximity focusing RICH with a silica aerogel radiator

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2007)

I. Adachi K. Fujita T. Fukushima A. Gorišek D. Hayashi

Radiator (engine cooling)

Particle identification

Cherenkov detector

Photoelectric effect

10.1016/j.nima.2007.08.017

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Citations (4)

ПОИСК НЕЙТРИНО УЛЬТРАВЫСОКИХ ЭНЕРГИЙ ПО ДАННЫМ НАЗЕМНОЙ РЕШЕТКИ ЭКСПЕРИМЕНТА TELESCOPE ARRAY

Журнал Экспериментальной и Теоретической Физики (2020)

Rasha Abbasi M. Abe T. Abu‐Zayyad M. Allen R. Azuma

10.31857/s0044451020080052

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Citations (3)

Measurement of the neutron beam polarization of BL05/NOP beamline at J-PARC

Physica B Condensed Matter (2011)

Takashi Ino Y. Arimoto T. Yoshioka K. Mishima K. Taketani

J-PARC

NOP

10.1016/j.physb.2011.01.009

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Citations (9)

Search for point sources of ultra-high-energy photons with the Telescope Array surface detector

Monthly Notices of the Royal Astronomical Society (2019)

Rasha Abbasi Mitsuru Abe T. Abu‐Zayyad M. Allen R. Azuma

The surface detector (SD) of the Telescope Array (TA) experiment allows one to indirectly detect photons with energies of order $10^{18}$ eV and higher and to separate photons from the cosmic-ray background. In this paper we present the results of a blind search for point sources of ultra-high energy (UHE) photons in the Northern sky using the TA SD data. The photon-induced extensive air showers (EAS) are separated from the hadron-induced EAS background by means of a multivariate classifier based upon 16 parameters that characterize the air shower events. No significant evidence for the photon point sources is found. The upper limits are set on the flux of photons from each particular direction in the sky within the TA field of view, according to the experiment's angular resolution for photons. Average 95% C.L. upper limits for the point-source flux of photons with energies greater than $10^{18}$, $10^{18.5}$, $10^{19}$, $10^{19.5}$ and $10^{20}$ eV are $0.094$, $0.029$, $0.010$, $0.0073$ and $0.0058$ km$^{-2}$yr$^{-1}$ respectively. For the energies higher than $10^{18.5}$ eV, the photon point-source limits are set for the first time. Numerical results for each given direction in each energy range are provided as a supplement to this paper.

Air shower

Point source

10.1093/mnras/stz3618

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Citations (9)

Properties of the X(3872) at Belle

Talk given at (2004)

Kazuo Abe Heyoung Yang Y. Chao D. Žontar D. Liventsev

X(3872)

Source

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Citations (1)

First High‐Speed Video Camera Observations of a Lightning Flash Associated With a Downward Terrestrial Gamma‐Ray Flash

Geophysical Research Letters (2023)

Rasha Abbasi Marcelo M. F. Saba John Belz P. R. Krehbiel W. Rison

Abstract In this paper, we present the first high‐speed video observation of a cloud‐to‐ground lightning flash and its associated downward‐directed Terrestrial Gamma‐ray Flash (TGF). The optical emission of the event was observed by a high‐speed video camera running at 40,000 frames per second in conjunction with the Telescope Array Surface Detector, Lightning Mapping Array, interferometer, electric‐field fast antenna, and the National Lightning Detection Network. The cloud‐to‐ground flash associated with the observed TGF was formed by a fast downward leader followed by a very intense return stroke peak current of −154 kA. The TGF occurred while the downward leader was below cloud base, and even when it was halfway in its propagation to ground. The suite of gamma‐ray and lightning instruments, timing resolution, and source proximity offer us detailed information and therefore a unique look at the TGF phenomena.

Lightning

Lightning detection

Upper-atmospheric lightning

10.1029/2023gl102958

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Citations (9)

The UHECR dipole and quadrupole in the latest data from the original Auger and TA surface detectors

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2021)

P. Tinyakov Rogério de Almeida Rasha Abbasi T. Abu‐Zayyad Monica Allen

The sources of ultra-high-energy cosmic rays are still unknown, but assuming standard physics, they are expected to lie within a few hundred megaparsecs from us. Indeed, over cosmological distances cosmic rays lose energy to interactions with background photons, at a rate depending on their mass number and energy and properties of photonuclear interactions and photon backgrounds. The universe is not homogeneous at such scales, hence the distribution of the arrival directions of cosmic rays is expected to reflect the inhomogeneities in the distribution of galaxies; the shorter the energy loss lengths, the stronger the expected anisotropies. Galactic and intergalactic magnetic fields can blur and distort the picture, but the magnitudes of the largest-scale anisotropies, namely the dipole and quadrupole moments, are the most robust to their effects. Measuring them with no bias regardless of any higher-order multipoles is not possible except with full-sky coverage. In this work, we achieve this in three energy ranges (approximately 8--16 EeV, 16--32 EeV, and 32--$\infty$ EeV) by combining surface-detector data collected at the Pierre Auger Observatory until 2020 and at the Telescope Array (TA) until 2019, before the completion of the upgrades of the arrays with new scintillator detectors. We find that the full-sky coverage achieved by combining Auger and TA data reduces the uncertainties on the north-south components of the dipole and quadrupole in half compared to Auger-only results.

Pierre Auger Observatory

10.22323/1.395.0375

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Citations (13)

Intermediate Fluence Downward Terrestrial Gamma Ray Flashes as Observed by the Telescope Array Surface Detector

Journal of Geophysical Research Atmospheres (2024)

Rasha Abbasi N. Kieu P. R. Krehbiel J. W. Belz Marcelo M. F. Saba

Abstract On 11 September 2021, two small thunderstorms developed over the Telescope Array Surface Detector (TASD) that produced an unprecedented number of six downward terrestrial gamma ray flashes (TGFs) within one‐hour timeframe. The TGFs occurred during the initial stage of negative cloud‐to‐ground flashes whose return strokes had increasingly large peak currents up to 223 kA, 147 GeV energy deposit in up to 25 1.2 km‐spaced surface detectors, and intermittent bursts of gamma‐rays with total durations up to 717 s. The analyses are based on observations recorded by the TASD network, complemented by data from a 3D lightning mapping array, broadband VHF interferometer, fast electric field change sensor, high‐speed video camera, and the National Lightning Detection Network. The TGFs of the final two flashes had gamma fluences of and 8, logarithmically bridging the gap between previous TASD and satellite‐based detections. The observations further emphasize the similarity between upward and downward TGF varieties, suggesting a common mechanism for their production.

10.1029/2024jd041260

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Citations (0)