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33 results on '"Wada, Y."'

1. Limits on astrophysical antineutrinos with the KamLAND experiment

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kinoshita, T., Kishimoto, Y., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Kozlov, A., Chernyak, D., Takemoto, Y., Yoshida, S., Umehara, S., Fushimi, K., Hirata, S., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. L., Learned, J. G., Maricic, J., Axani, S. N., Fu, Z., Ouellet, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Dell'Oro, S., and O'donnell, T.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

We report on a search for electron antineutrinos ($\bar{\nu}_e$) from astrophysical sources in the neutrino energy range 8.3 to 30.8 MeV with the KamLAND detector. In an exposure of 6.72 kton-year of the liquid scintillator, we observe 18 candidate events via the inverse beta decay reaction. Although there is a large background uncertainty from neutral current atmospheric neutrino interactions, we find no significant excess over background model predictions. Assuming several supernova relic neutrino spectra, we give upper flux limits of 60--110 cm$^{-2}$ s$^{-1}$ (90% CL) in the analysis range and present a model-independent flux. We also set limits on the annihilation rates for light dark matter pairs to neutrino pairs. These data improves on the upper probability limit of $^{8}$B solar neutrinos converting into $\bar{\nu}_e$'s, $P_{\nu_e \rightarrow \bar{\nu}_e} < 3.5\times10^{-5}$ (90% CL) assuming an undistorted $\bar{\nu}_e$ shape. This corresponds to a solar $\bar{\nu}_e$ flux of 60 cm$^{-2}$ s$^{-1}$ (90% CL) in the analysis energy range., Comment: 21 pages, 9 figures, 4 tables, accepted for publication in Astrophysical Journal

Published
2021
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2. Search for Solar Flare Neutrinos with the KamLAND detector

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Kinoshita, T., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Kozlov, A., Chernyak, D., Takemoto, Y., Yoshida, S., Umehara, S., Fushimi, K., Ichikawa, A. K., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Winslow, L. A., Fu, Z., Ouellet, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., O'Donnell, T., and Dell'Oro, S.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We report the result of a search for neutrinos in coincidence with solar flares from the GOES flare database. The search was performed on a 10.8 kton-year exposure of KamLAND collected from 2002 to 2019. This large exposure allows us to explore previously unconstrained parameter space for solar flare neutrinos. We found no statistical excess of neutrinos and established 90% confidence level upper limits of $8.4 \times 10^7$ cm$^{-2}$ ($3.0 \times 10^{9}$ cm$^{-2}$) on electron anti-neutrino (electron neutrino) fluence at 20 MeV normalized to the X12 flare, assuming that the neutrino fluence is proportional to the X-ray intensity., Comment: 13 pages, 9 figures, accepted October 27, 2021

Published
2021
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3. The nylon balloon for xenon loaded liquid scintillator in KamLAND-Zen 800 neutrinoless double-beta decay search experiment

Author

collaboration, KamLAND-Zen, Gando, Y., Gando, A., Hachiya, T., Hayashida, S., Hosokawa, K., Ikeda, H., Mitsui, T., Nakada, T., Obara, S., Ozaki, H., Shirai, J., Ueshima, K., Watanabe, H., Abe, S., Hata, K., Hayashi, A., Honda, Y., Ieki, S., Inoue, K., Ishidoshiro, K., Ishikawa, S., Kamei, Y., Kamizawa, K., Karino, Y., Kawada, N., Kinoshita, T., Koga, M., Matsuda, S., Miyake, H., Nakamura, K., Nemoto, K., Ono, A., Ota, N., Otsuka, S., Shibukawa, Y., Shimizu, I., Shirahata, Y., Soma, K., Suzuki, A., Suzuki, A. A., Takai, T., Takeuchi, A., Tamae, K., Teraoka, Y., Wada, Y., Chernyak, D., Kozlov, A., Yoshida, S., Umehara, S., Takemoto, Y., Fushimi, K., Hirata, S., Grant, C., Li, A., Learned, J. G., Maricic, J., Berger, B. E., Fujikawa, B. K., Fraker, S., Herman, A., Krupczak, E., Pease, G. L., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., O'Donnell, T., Dell'Oro, S., Detwiler, J. A., Enomoto, S., and Decowski, M. P.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract

The KamLAND-Zen 800 experiment is searching for the neutrinoless double-beta decay of $^{136}$Xe by using $^{136}$Xe-loaded liquid scintillator. The liquid scintillator is enclosed inside a balloon made of thin, transparent, low-radioactivity film that we call Inner Balloon (IB). The IB, apart from guaranteeing the liquid containment, also allows to minimize the background from cosmogenic muon-spallation products and $^{8}$B solar neutrinos. Indeed these events could contribute to the total counts in the region of interest around the Q-value of the double-beta decay of $^{136}$Xe. In this paper, we present an overview of the IB and describe the various steps of its commissioning minimizing the radioactive contaminations, from the material selection, to the fabrication of the balloon and its installation inside the KamLAND detector. Finally, we show the impact of the IB on the KamLAND background as measured by the KamLAND detector itself., Comment: 23 pages, 16 figures, to be submitted to JINST

Published
2021
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4. Proton-$\rm ^3He$ elastic scattering at intermediate energies

Author

Watanabe, A., Nakai, S., Wada, Y., Sekiguchi, K., Deltuva, A., Akieda, T., Etoh, D., Inoue, M., Inoue, Y., Kawahara, K., Kon, H., Miki, K., Mukai, T., Sakai, D., Shibuya, S., Shiokawa, Y., Taguchi, T., Umetsu, H., Utsuki, Y., Watanabe, M., Goto, S., Hatanaka, K., Hirai, Y., Ino, T., Inomoto, D., Inoue, A., Ishikawa, S., Itoh, M., Kanda, H., Kasahara, H., Kobayashi, N., Maeda, Y., Mitsumoto, S., Nakamura, S., Nonaka, K., Ong, H. J., Oshiro, H., Otake, Y., Sakai, H., Taketani, A., Tamii, A., Tran, D. T., Wakasa, T., Wakabayashi, Y., and Wakui, T.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

We present a precise measurement of the cross section, proton and $\rm ^3He$ analyzing powers, and spin correlation coefficient $C_{y,y}$ for $p$-$\rm ^3He$ elastic scattering near 65 MeV, and a comparison with rigorous four-nucleon scattering calculations based on realistic nuclear potentials and a model with $\Delta$-isobar excitation. Clear discrepancies are seen in some of the measured observables in the regime around the cross section minimum. Theoretical predictions using scaling relations between the calculated cross section and the $\rm ^3 He$ binding energy are not successful in reproducing the data. Large sensitivity to the $NN$ potentials and rather small $\Delta$-isobar effects in the calculated cross section are noticed as different features from those in the deuteron-proton elastic scattering. The results obtained above indicate that $p$-$\rm ^3He$ scattering at intermediate energies is an excellent tool to explore nuclear interactions not accessible by three-nucleon scattering., Comment: 22 pages, 6 figures

Published
2021
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5. A Search for Charged Excitation of Dark Matter with the KamLAND-Zen Detector

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kinoshita, T., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ono, A., Ota, N., Otsuka, S., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirahata, Y., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Chernyak, D., Kozlov, A., Yoshida, S., Umehara, S., Takemoto, Y., Fushimi, K., Hirata, S., Ichikawa, A., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. K., Grant, C., Li, A., Learned, J. G., Maricic, J., Axani, S., Winslow, L. A., Fu, Z., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., ODonnell, T., DellOro, S., Detwiler, J. A., Enomoto, S., and Decowski, M. P.

Subjects
High Energy Physics - Experiment
Abstract

There are many theories where a dark matter particle is part of a multiplet with an electrically charged state. If WIMP dark matter ($\chi^{0}$) is accompanied by a charged excited state ($\chi^{-}$) separated by a small mass difference, it can form a stable bound state with a nucleus. In supersymmetric models, the $\chi^{0}$ and the $\chi^{-}$ could be the neutralino and a charged slepton, such as the neutralino-stau degenerate model. The formation binding process is expected to result in an energy deposition of {\it O}(1--10 MeV), making it suitable for detection in large liquid scintillator detectors. We describe new constraints on the bound state formation with a xenon nucleus using the KamLAND-Zen 400 Phase-II dataset. In order to enlarge the searchable parameter space, all xenon isotopes in the detector were used. For a benchmark parameter set of $m_{\chi^{0}} = 100$ GeV and $\Delta m = 10$ MeV, this study sets the most stringent upper limits on the recombination cross section $\langle\sigma v\rangle$ and the decay-width of $\chi^{-}$ of $2.0 \times 10^{-31}$ ${\rm cm^3/s}$ and $1.1 \times 10^{-18}$ GeV, respectively (90\% confidence level).

Published
2021

6. Search for Low-energy Electron Antineutrinos in KamLAND Associated with Gravitational Wave Events

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Kinoshita, T., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Kozlov, A., Chernyak, D., Takemoto, Y., Yoshida, S., Umehara, S., Fushimi, K., Ichikawa, A. K., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S., Winslow, L. A., Fu, Z., Ouellet, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., O'Donnell, T., and Dell'Oro, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

We present the results of a search for MeV-scale electron antineutrino events in KamLAND in coincident with the 60 gravitational wave events/candidates reported by the LIGO/Virgo collaboration during their second and third observing runs. We find no significant coincident signals within a $\pm$ 500 s timing window from each gravitational wave and present 90% C.L. upper limits on the electron antineutrino fluence between $10^{8}$-$10^{13}\,{\mathrm cm^2}$ for neutrino energies in the energy range of 1.8-111 MeV., Comment: 11 pages, 2 figures, 2 tables, Accepted for publication in ApJ

Published
2020
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7. Measurement of 3He analyzing power for p-3He scattering using the polarized 3He target

Author

Watanabe, A., Nakai, S., Sekiguchi, K., Akieda, T., Etoh, D., Inoue, M., Inoue, Y., Kawahara, K., Kon, H., Miki, K., Mukai, T., Sakai, D., Shibuya, S., Shiokawa, Y., Taguchi, T., Umetsu, H., Utsuki, Y., Wada, Y., Watanabe, M., Itoh, M., Ino, T., Wakui, T., Hatanaka, K., Kanda, H., Ong, H. J., Tran, D. T., Goto, S., Hirai, Y., Inomoto, D., Kasahara, H., Mitsumoto, S., Oshiro, H., Wakasa, T., Maeda, Y., Nonaka, K., Sakai, H., and Uesaka, T.

Subjects
Nuclear Experiment
Abstract

Proton-3He scattering is one of the good probes to study the T=3/2 channel of three--nucleon forces. We have measured 3He analyzing powers for p-3He elastic scattering with the polarized 3He target at 70 and 100 MeV. The data are compared with the theoretical predictions based on the modern nucleon--nucleon potentials. Large discrepancies are found between the data and the calculations at the angles where the 3He analyzing power takes the minimum and maximum values, which are not explained by taking into account Delta-isobar degrees of freedom., Comment: 7pages, 3 figures Submission to SciPost

Published
2019

8. Conditional stability for an inverse source problem and an application to the estimation of air dose rate radioactive substances by drone data

Author

Chen, Y., Cheng, J., Floridia, G., Wada, Y., and Yamamoto, M.

Subjects
Mathematics - Analysis of PDEs
Abstract

We consider the density field $f(x)$ generated by a volume source $\mu(y)$ in $D$ which is a domain in $\R^3$. For two disjoint segments $\gamma, \Gamma_1$ on a straight line in $\R^3 \setminus \ooo{D}$, we establish a conditional stability estimate of H\"older type in determining $f$ on $\Gamma_1$ by data $f$ on $\gamma$. This is a theoretical background for real-use solutions for the determination of air dose rates of radioactive substance at the human height level by high-altitude data. The proof of the stability estimate is based on the harmonic extension and the stability for line unique continuation of a harmonic function.

Published
2019

9. Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the 'D-shuttle' project --

Author

Adachi, N., Adamovitch, V., Adjovi, Y., Aida, K., Akamatsu, H., Akiyama, S., Akli, A., Ando, A., Andrault, T., Antonietti, H., Anzai, S., Arkoun, G., Avenoso, C., Ayrault, D., Banasiewicz, M., Banaśkiewicz, M., Bernandini, L., Bernard, E., Berthet, E., Blanchard, M., Boreyko, D., Boros, K., Charron, S., Cornette, P., Czerkas, K., Dameron, M., Date, I., De Pontbriand, M., Demangeau, F., Dobaczewski, Ł., Dobrzyński, L., Ducouret, A., Dziedzic, M., Ecalle, A., Edon, V., Endo, K., Endo, T., Endo, Y., Etryk, D., Fabiszewska, M., Fang, S., Fauchier, D., Felici, F., Fujiwara, Y., Gardais, C., Gaul, W., Guérin, L., Hakoda, R., Hamamatsu, I., Handa, K., Haneda, H., Hara, T., Hashimoto, M., Hashimoto, T., Hashimoto, K., Hata, D., Hattori, M., Hayano, R., Hayashi, R., Higasi, H., Hiruta, M., Honda, A., Horikawa, Y., Horiuchi, H., Hozumi, Y., Ide, M., Ihara, S., Ikoma, T., Inohara, Y., Itazu, M., Ito, A., Janvrin, J., Jout, I., Kanda, H., Kanemori, G., Kanno, M., Kanomata, N., Kato, T., Kato, S., Katsu, J., Kawasaki, Y., Kikuchi, K., Kilian, P., Kimura, N., Kiya, M., Klepuszewski, M., Kluchnikov, E., Kodama, Y., Kokubun, R., Konishi, F., Konno, A., Kontsevoy, V., Koori, A., Koutaka, A., Kowol, A., Koyama, Y., Kozioł, M., Kozue, M., Kravtchenko, O., Kruczała, W., Kudła, M., Kudo, H., Kumagai, R., Kurogome, K., Kurosu, A., Kuse, M., Lacombe, A., Lefaillet, E., Magara, M., Malinowska, J., Malinowski, M., Maroselli, V., Masui, Y., Matsukawa, K., Matsuya, K., Matusik, B., Maulny, M., Mazur, P., Miyake, C., Miyamoto, Y., Miyata, K., Miyazaki, M., Molęda, M., Morioka, T., Morita, E., Muto, K., Nadamoto, H., Nadzikiewicz, M., Nagashima, K., Nakade, M., Nakayama, C., Nakazawa, H., Nihei, Y., Nikul, R., Niwa, S., Niwa, O., Nogi, M., Nomura, K., Ogata, D., Ohguchi, H., Ohno, J., Okabe, M., Okada, M., Okada, Y., Omi, N., Onodera, H., Onodera, K., Ooki, S., Oonishi, K., Oonuma, H., Ooshima, H., Oouchi, H., Orsucci, M., Paoli, M., Penaud, M., Perdrisot, C., Petit, M., Piskowski, A., Płocharski, A., Polis, A., Polti, L., Potsepnia, T., Przybylski, D., Pytel, M., Quillet, W., Remy, A., Robert, C., Sadowski, M., Saito, M., Sakuma, D., Sano, K., Sasaki, Y., Sato, N., Schneider, T., Schneider, C., Schwartzman, K., Selivanov, E., Sezaki, M., Shiroishi, K., Shustava, I., Śniecińska, A., Stalchenko, E., Staroń, A., Stromboni, M., Studzińska, W., Sugisaki, H., Sukegawa, T., Sumida, M., Suzuki, Y., Suzuki, K., Suzuki, R., Suzuki, H., Świderski, W., Szudejko, M., Szymaszek, M., Tada, J., Taguchi, H., Takahashi, K., Tanaka, D., Tanaka, G., Tanaka, S., Tanino, K., Tazbir, K., Tcesnokova, N., Tgawa, N., Toda, N., Tsuchiya, H., Tsukamoto, H., Tsushima, T., Tsutsumi, K., Umemura, H., Uno, M., Usui, A., Utsumi, H., Vaucelle, M., Wada, Y., Watanabe, K., Watanabe, S., Watase, K., Witkowski, M., Yamaki, T., Yamamoto, J., Yamamoto, T., Yamashita, M., Yanai, M., Yasuda, K., Yoshida, Y., Yoshida, A., Yoshimura, K., Żmijewska, M., and Zuclarelli, E.

Subjects
Physics - Medical Physics
Abstract

Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the background radiation level of other regions/countries.

Published
2015
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10. Pierre Auger Observatory and Telescope Array: Joint Contributions to the 33rd International Cosmic Ray Conference (ICRC 2013)

Author

Array, The Telescope, Collaborations, Pierre Auger, Abu-Zayyad, T., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W, Bergman, D. R., Blake, S. A., Cady, R., Chae, M. J., Cheon, B. G., Chiba, J., Chikawa, M., Cho, W. R., Fujii, T., Fukushima, M., Goto, K., Hanlon, W., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kitamura, S., Kitamura, Y., Kuzmin, V., Kwon, Y. J., Lan, J., Lundquist, J. P., Machida, K., Martens, K., Matsuda, T., Matsuyama, T., Matthews, J. N., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nanpei, H., Nonaka, T., Nozato, A., Ogio, S., Oh, S., Ohnishi, M., Ohoka, H., Oki, K., Okuda, T., Ono, M., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shirahama, T., Smith, J. D., Sokolsky, P., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T. A., Takamura, M., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Vasiloff, G., Wada, Y., Wong, T., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zollinger, R., Zundel, Z., Aab, A., Abreu, P., Aglietta, M., Ahlers, M., Ahn, E. J., Albuquerque, I. F. M., Allekotte, I., Allen, J., Allison, P., Almela, A., Castillo, J. Alvarez, Alvarez-Muniz, J., Batista, R. Alves, Ambrosio, M., Aminaei, A., Anchordoqui, L., Andringa, S., Antivcic, T., Aramo, C., Arqueros, F., Asorey, H., Assis, P., Aublin, J., Ave, M., Avenier, M., Avila, G., Badescu, A. M., Barber, K. B., Bardenet, R., Baeuml, J., Baus, C., Beatty, J. J., Becker, K. H., Belletoile, A., Bellido, J. A., BenZvi, S., Berat, C., Bertou, X., Biermann, P. L., Billoir, P., Blanco, F., Blanco, M., Bleve, C., Blumer, H., Bohacova, M., Boncioli, D., Bonifazi, C., Bonino, R., Borodai, N., Brack, J., Brancus, I., Brogueira, P., Brown, W. C., Buchholz, P., Bueno, A., Burton, R. E., Buscemi, M., Caballero-Mora, K. S., Caccianiga, B., Caccianiga, L., Candusso, M., Caramete, L., Caruso, R., Castellina, A., Cataldi, G., Cazon, L., Cester, R., Cheng, S. H., Chiavassa, A., Chinellato, J. A., Chudoba, J., Cilmo, M., Clay, R. W., Cocciolo, G., Colalillo, R., Collica, L., Coluccia, M. R., Conceicao, R., Contreras, F., Cook, H., Cooper, M. J., Coutu, S., Covault, C. E., Criss, A., Cronin, J., Curutiu, A., Dallier, R., Daniel, B., Dasso, S., Daumiller, K., Dawson, B. R., de Almeida, R. M., De Domenico, M., de Jong, S. J., De La Vega, G., Junior, W. J. M. de Mello, Neto, J. R. T. de Mello, De Mitri, I., de Souza, V., de Vries, K. D., del Peral, L., Deligny, O., Dembinski, H., Dhital, N., Di Giulio, C., Diaz, J. C., Castro, M. L. Diaz, Diep, P. N., Diogo, F., Dobrigkeit, C., Docters, W., D'Olivo, J. C., Dong, P. N., Dorofeev, A., Anjos, J. C. dos, Dova, M. T., Ebr, J., Engel, R., Erdmann, M., Escobar, C. O., Espadanal, J., Etchegoyen, A., Luis, P. Facal San, Falcke, H., Fang, K., Farrar, G., Fauth, A. C., Fazzini, N., Ferguson, A. P., Fick, B., Figueira, J. M., Filevich, A., Filipcic, A., Foerster, N., Fox, B. D., Fracchiolla, C. E., Fraenkel, E. D., Fratu, O., Frohlich, U., Fuchs, B., Gaior, R., Gamarra, R. F., Gambetta, S., Garcia, B., Roca, S. T. Garcia, Garcia-Gamez, D., Garcia-Pinto, D., Garilli, G., Bravo, A. Gascon, Gemmeke, H., Ghia, P. L., Giller, M., Gitto, J., Glaser, C., Glass, H., Albarracin, F. Gomez, Berisso, M. Gomez, Vitale, P. F. Gomez, Goncalves, P., Gonzalez, J. G., Gookin, B., Gorgi, A., Gorham, P., Gouffon, P., Grebe, S., Griffith, N., Grillo, A. F., Grubb, T. D., Guardincerri, Y., Guarino, F., Guedes, G. P., Hansen, P., Harari, D., Harrison, T. A., Harton, J. L., Haungs, A., Hebbeker, T., Heck, D., Herve, A. E., Hill, G. C., Hojvat, C., Hollon, N., Homola, P., Hoerandel, J. R., Horvath, P., Hrabovsky, M., Huber, D., Huege, T., Insolia, A., Isar, P. G., Jansen, S., Jarne, C., Josebachuili, M., Kadija, K., Kambeitz, O., Kampert, K. H., Karhan, P., Kasper, P., Katkov, I., Kegl, B., Keilhauer, B., Keivani, A., Kemp, E., Kieckhafer, R. M., Klages, H. O., Kleifges, M., Kleinfeller, J., Knapp, J., Krause, R., Krohm, N., Kroemer, O., Kruppke-Hansen, D., Kuempel, D., Kunka, N., La Rosa, G., LaHurd, D., Latronico, L., Lauer, R., Lauscher, M., Lautridou, P., Coz, S. Le, Leao, M. S. A. B., Lebrun, D., Lebrun, P., de Oliveira, M. A. Leigui, Letessier-Selvon, A., Lhenry-Yvon, I., Link, K., Lopez, R., Aguera, A. Lopez, Louedec, K., Bahilo, J. Lozano, Lu, L., Lucero, A., Ludwig, M., Lyberis, H., Maccarone, M. C., Macolino, C., Malacari, M., Maldera, S., Maller, J., Mandat, D., Mantsch, P., Mariazzi, A. G., Marin, V., Maris, I. C., Falcon, H. R. Marquez, Marsella, G., Martello, D., Martin, L., Martinez, H., Bravo, O. Martinez, Martraire, D., Meza, J. J. Masias, Mathes, H. J., Matthews, J., Matthews, J. A. J., Matthiae, G., Maurel, D., Maurizio, D., Mayotte, E., Mazur, P. O., Medina, C., Medina-Tanco, G., Melissas, M., Melo, D., Menichetti, E., Menshikov, A., Messina, S., Meyhandan, R., Micanovic, S., Micheletti, M. I., Middendorf, L., Minaya, I. A., Miramonti, L., Mitrica, B., Molina-Bueno, L., Mollerach, S., Monasor, M., Ragaigne, D. Monnier, Montanet, F., Morales, B., Morello, C., Moreno, J. C., Mostafa, M., Moura, C. A., Muller, M. A., Muller, G., Munchmeyer, M., Mussa, R., Navarra, G., Navarro, J. L., Navas, S., Necesal, P., Nellen, L., Nelles, A., Neuser, J., Nhung, P. T., Niechciol, M., Niemietz, L., Niggemann, T., Nitz, D., Nosek, D., Novzka, L., Oehlschlager, J., Olinto, A., Oliveira, M., Ortiz, M., Pacheco, N., Selmi-Dei, D. Pakk, Palatka, M., Pallotta, J., Palmieri, N., Parente, G., Parra, A., Pastor, S., Paul, T., Pech, M., Pekala, J., Pelayo, R., Pepe, I. M., Perrone, L., Pesce, R., Petermann, E., Petrera, S., Petrolini, A., Petrov, Y., Piegaia, R., Pierog, T., Pieroni, P., Pimenta, M., Pirronello, V., Platino, M., Plum, M., Pontz, M., Porcelli, A., Preda, T., Privitera, P., Prouza, M., Quel, E. J., Querchfeld, S., Quinn, S., Rautenberg, J., Ravel, O., Ravignani, D., Revenu, B., Ridky, J., Riggi, S., Risse, M., Ristori, P., Rivera, H., Rizi, V., Roberts, J., de Carvalho, W. Rodrigues, Cabo, I. Rodriguez, Fernandez, G. Rodriguez, Martino, J. Rodriguez, Rojo, J. Rodriguez, Rodriguez-Frias, M. D., Ros, G., Rosado, J., Rossler, T., Roth, M., Rouille-d'Orfeuil, B., Roulet, E., Rovero, A. C., Ruhle, C., Saffi, S. J., Saftoiu, A., Salamida, F., Salazar, H., Greus, F. Salesa, Salina, G., Sanchez, F., Sanchez-Lucas, P., Santo, C. E., Santos, E., Santos, E. M., Sarazin, F., Sarkar, B., Sato, R., Scharf, N., Scherini, V., Schieler, H., Schiffer, P., Schmidt, A., Scholten, O., Schoorlemmer, H., Schovanek, P., Schroeder, F. G., Schulz, A., Schulz, J., Sciutto, S. J., Scuderi, M., Segreto, A., Settimo, M., Shadkam, A., Shellard, R. C., Sidelnik, I., Sigl, G., Sima, O., Smialkowski, A., Smida, R., Snow, G. R., Sommers, P., Sorokin, J., Spinka, H., Squartini, R., Srivastava, Y. N., Stanic, S., Stapleton, J., Stasielak, J., Stephan, M., Straub, M., Stutz, A., Suarez, F., Suomijarvi, T., Supanitsky, A. D., Susa, T., Sutherland, M. S., Swain, J., Szadkowski, Z., Szuba, M., Tapia, A., Tartare, M., Tacscuau, O., Tcaciuc, R., Thao, N. T., Tiffenberg, J., Timmermans, C., Tkaczyk, W., Peixoto, C. J. Todero, Toma, G., Tomankova, L., Tome, B., Tonachini, A., Elipe, G. Torralba, Machado, D. Torres, Travnicek, P., Tridapalli, D. B., Trovato, E., Tueros, M., Ulrich, R., Unger, M., Galicia, J. F. Valdes, Valino, I., Valore, L., van Aar, G., Berg, A. M. van den, van Velzen, S., van Vliet, A., Varela, E., Cardenas, B. Vargas, Varner, G., Vazquez, J. R., Vazquez, R. A., Veberic, D., Verzi, V., Vicha, J., Videla, M., Villasenor, L., Wahlberg, H., Wahrlich, P., Wainberg, O., Walz, D., Watson, A. A., Weber, M., Weidenhaupt, K., Weindl, A., Werner, F., Westerhoff, S., Whelan, B. J., Widom, A., Wieczorek, G., Wiencke, L., Wilczynska, B., Wilczynski, H., Will, M., Williams, C., Winchen, T., Wundheiler, B., Wykes, S., Yamamoto, T., Yapici, T., Younk, P., Yuan, G., Yushkov, A., Zamorano, B., Zas, E., Zavrtanik, D., Zavrtanik, M., Zaw, I., Zepeda, A., Zhou, J., Zhu, Y., Silva, M. Zimbres, and Ziolkowski, M.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Joint contributions of the Pierre Auger and Telescope Array Collaborations to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013: cross-calibration of the fluorescence telescopes, large scale anisotropies and mass composition., Comment: Joint contributions of the Pierre Auger and Telescope Array Collaborations to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013

Published
2013

11. Search for correlations of the arrival directions of ultra-high energy cosmic ray with extragalactic objects as observed by the telescope array experiment

Author

Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kitamura, S., Kitamura, Y., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lan, J., Lim, S. I., Lundquist, J. P., Machida, S., Martens, K., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Minamino, M., Miyata, K., Murano, Y., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Ono, M., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Roh, S. Y., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Urban, F., Vasiloff, G., Wada, Y., Wong, T., Yamakawa, Y., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yoneda, Y., Yoshida, S., Yoshii, H., Zhou, X., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We search for correlations between positions of extragalactic objects and arrival directions of Ultra-High Energy Cosmic Rays (UHECRs) with primary energy $E \ge 40$ EeV as observed by the surface detector array of the Telescope Array (TA) experiment during the first 40 months of operation. We examined several public astronomical object catalogs, including the Veron-Cetty and Veron catalog of active galactic nuclei. We counted the number of TA events correlated with objects in each catalog as a function of three parameters: the maximum angular separation between a TA event and an object, the minimum energy of the events, and the maximum redshift of the objects. We determine combinations of these parameters which maximize the correlations, and calculate the chance probabilities of having the same levels of correlations from an isotropic distribution of UHECR arrival directions. No statistically significant correlations are found when penalties for scanning over the above parameters and for searching in several catalogs are taken into account.

Published
2013
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12. Energy Spectrum of Ultra-High Energy Cosmic Rays Observed with the Telescope Array Using a Hybrid Technique

Author

Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kitamura, S., Kitamura, Y., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lan, J., Lim, S. I., Lundquist, J. P., Machida, S., Martens, K., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Minamino, M., Miyata, K., Murano, Y., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Ono, M., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Roh, S. Y., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Urban, F., Vasiloff, G., Wada, Y., Wong, T., Yamakawa, Y., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yoneda, Y., Yoshida, S., Yoshii, H., Zhou, X., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We measure the spectrum of cosmic rays with energies greater than $10^{18.2}$ eV with the Fluorescence Detectors (FDs) and the Surface Detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27 2008 to September 7 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results., Comment: 28 pages, 12 figures, submitted to Astroparticle Physics

Published
2013

13. The Energy Spectrum of Ultra-High-Energy Cosmic Rays Measured by the Telescope Array FADC Fluorescence Detectors in Monocular Mode

Author

The Telescope Array Collaboration, Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kitamura, S., Kitamura, Y., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lan, J., Lim, S. I., Lundquist, J. P., Machida, S., Martens, K., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Myers, I., Minamino, M., Miyata, K., Murano, Y., Nagataki, S., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Ono, M., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Roh, S. Y., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Sonley, T. J., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Vasiloff, G., Wada, Y., Wong, T., Yamakawa, Y., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yoneda, Y., Yoshida, S., Yoshii, H., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array's third fluorescence detector (Abu-Zayyad {\it et al.}, {Astropart. Phys.} 39 (2012), 109). This combined spectrum corroborates the recently published Telescope Array surface detector spectrum (Abu-Zayyad {\it et al.}, {Astrophys. Journ.} 768 (2013), L1) with independent systematic uncertainties., Comment: 10 pages, 10 figures, submitted to Astroparticle Physics

Published
2013

14. Upper limit on the flux of photons with energies above 10^19 eV using the Telescope Array surface detector

Author

Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Gorbunov, D., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kitamura, S., Kitamura, Y., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lan, J., Lim, S. I., Machida, S., Martens, K., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Minamino, M., Miyata, K., Murano, Y., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Roh, S. Y., Rubtsov, G. I., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Vasiloff, G., Wada, Y., Wong, T., Wood, M., Yamakawa, Y., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yoneda, Y., Yoshida, S., Yoshii, H., Zhou, X., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

We search for ultra-high energy photons by analyzing geometrical properties of shower fronts of events registered by the Telescope Array surface detector. By making use of an event-by-event statistical method, we derive upper limits on the absolute flux of primary photons with energies above 10^19, 10^19.5 and 10^20 eV based on the first three years of data taken., Comment: 7 pages, 5 figures

Published
2013
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15. Search for Anisotropy of Ultra-High Energy Cosmic Rays with the Telescope Array Experiment

Author

Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kitamura, S., Kitamura, Y., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lim, S. I., Machida, S., Martens, K., Martineau, J., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Minamino, M., Miyata, K., Murano, Y., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Roh, S. Y., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Sonley, T. J., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Vasiloff, G., Wada, Y., Wong, T., Wood, M., Yamakawa, Y., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yoneda, Y., Yoshida, S., Yoshii, H., Zhou, X., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We study the anisotropy of Ultra-High Energy Cosmic Ray (UHECR) events collected by the Telescope Array (TA) detector in the first 40 months of operation. Following earlier studies, we examine event sets with energy thresholds of 10 EeV, 40 EeV, and 57 EeV. We find that the distributions of the events in right ascension and declination are compatible with an isotropic distribution in all three sets. We then compare with previously reported clustering of the UHECR events at small angular scales. No significant clustering is found in the TA data. We then check the events with E>57 EeV for correlations with nearby active galactic nuclei. No significant correlation is found. Finally, we examine all three sets for correlations with the large-scale structure of the Universe. We find that the two higher-energy sets are compatible with both an isotropic distribution and the hypothesis that UHECR sources follow the matter distribution of the Universe (the LSS hypothesis), while the event set with E>10 EeV is compatible with isotropy and is not compatible with the LSS hypothesis at 95% CL unless large deflection angles are also assumed. We show that accounting for UHECR deflections in a realistic model of the Galactic magnetic field can make this set compatible with the LSS hypothesis., Comment: 10 pages, 9 figures

Published
2012
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16. The Cosmic Ray Energy Spectrum Observed with the Surface Detector of the Telescope Array Experiment

Author

Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kitamura, S., Kitamura, Y., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lan, J., Lim, S. I., Machida, S., Martens, K., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Minamino, M., Miyata, K., Murano, Y., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Roh, S. Y., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Vasiloff, G., Wada, Y., Wong, T., Wood, M., Yamakawa, Y., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yoneda, Y., Yoshida, S., Yoshii, H., Zhou, X., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays with primary energies above 1.6 x 10^(18) eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 x 10^(18) eV and a steepening at 5.4 x 10^(19) eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of ultra-high energy cosmic ray surface detector data, that involves generating a complete simulation of ultra-high energy cosmic rays striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the "thinning" approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned., Comment: Accepted for publication by Astrophysical Journal Letters

Published
2012
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17. The Energy Spectrum of Telescope Array's Middle Drum Detector and the Direct Comparison to the High Resolution Fly's Eye Experiment

Author

Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Gorbunov, D., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kitamura, S., Kitamura, Y., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lim, S. I., Machida, S., Martens, K., Martineau, J., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Minamino, M., Miyata, K., Murano, Y., Nagataki, S., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Roh, S. Y., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Sonley, T. J., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Vasiloff, G., Wada, Y., Wong, T., Wood, M., Yamakawa, Y., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yoneda, Y., Yoshida, S., Yoshii, H., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Telescope Array's Middle Drum fluorescence detector was instrumented with telescopes refurbished from the High Resolution Fly's Eye's HiRes-1 site. The data observed by Middle Drum in monocular mode was analyzed via the HiRes-1 profile-constrained geometry reconstruction technique and utilized the same calibration techniques enabling a direct comparison of the energy spectra and energy scales between the two experiments. The spectrum measured using the Middle Drum telescopes is based on a three-year exposure collected between December 16, 2007 and December 16, 2010. The calculated difference between the spectrum of the Middle Drum observations and the published spectrum obtained by the data collected by the HiRes-1 site allows the HiRes-1 energy scale to be transferred to Middle Drum. The HiRes energy scale is applied to the entire Telescope Array by making a comparison between Middle Drum monocular events and hybrid events that triggered both Middle Drum and the Telescope Array's scintillator Ground Array., Comment: 27 pages, 21 figures

Published
2012
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18. The surface detector array of the Telescope Array experiment

Author

Abu-Zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Cho, E. J., Cho, W. R., Fujii, H., Fujii, T., Fukuda, T., Fukushima, M., Gorbunov, D., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Honda, K., Iguchi, T., Ikeda, D., Ikuta, K., Inoue, N., Ishii, T., Ishimori, R., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kido, E., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lim, S. I., Machida, S., Martens, K., Martineau, J., Matsuda, T., Matsuura, T., Matsuyama, T., Matthews, J. N., Myers, I., Minamino, M., Miyata, K., Miyauchi, H., Murano, Y., Nakamura, T., Nam, S. W., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Okuda, T., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D., Roh, S. Y., Rubtsov, G., Ryu, D., Sagawa, H., Sakurai, N., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Sonley, T. J., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzuki, S., Takahashi, Y., Takeda, M., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Udo, S., Ukai, H., Vasiloff, G., Wada, Y., Wong, T., Wood, M., Yamakawa, Y., Yamaoka, H., Yamazaki, K., Yang, J., Yoshida, S., Yoshii, H., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Telescope Array (TA) experiment, located in the western desert of Utah,USA, is designed for observation of extensive air showers from extremely high energy cosmic rays. The experiment has a surface detector array surrounded by three fluorescence detectors to enable simultaneous detection of shower particles at ground level and fluorescence photons along the shower track. The TA surface detectors and fluorescence detectors started full hybrid observation in March, 2008. In this article we describe the design and technical features of the TA surface detector., Comment: 32 pages, 17 figures

Published
2012
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19. New air fluorescence detectors employed in the Telescope Array experiment

Author

Tokuno, H., Tameda, Y., Takeda, M., Kadota, K., Ikeda, D., Chikawa, M., Fujii, T., Fukushima, M., Honda, K., Inoue, N., Kakimoto, F., Kawana, S., Kido, E., Matthews, J. N., Nonaka, T., Ogio, S., Okuda, T., Ozawa, S., Sagawa, H., Sakurai, N., Shibata, T., Taketa, A., Thomas, S. B., Tomida, T., Tsunesada, Y., Udo, S., Abu-zayyad, T., Aida, R., Allen, M., Anderson, R., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Cho, E. J., Cho, W. R., Fujii, H., Fukuda, T., Gorbunov, D., Hanlon, W., Hayashi, K., Hayashi, Y., Hayashida, N., Hibino, K., Hiyama, K., Iguchi, T., Ikuta, K., Ishii, T., Ishimori, R., Ivanov, D., Iwamoto, S., Jui, C. C. H., Kalashev, O., Kanbe, T., Kasahara, K., Kawai, H., Kawakami, S., Kim, H. B., Kim, H. K., Kim, J. H., Kitamoto, K., Kobayashi, K., Kobayashi, Y., Kondo, Y., Kuramoto, K., Kuzmin, V., Kwon, Y. J., Lim, S. I., Machida, S., Martens, K., Martineau, J., Matsuda, T., Matsuura, T., Matsuyama, T., Myers, I., Minamino, M., Miyata, K., Miyauchi, H., Murano, Y., Nakamura, T., Nam, S. W., Ohnishi, M., Ohoka, H., Oki, K., Oku, D., Oshima, A., Park, I. H., Pshirkov, M. S., Rodriguez, D., Roh, S. Y., Rubtsov, G., Ryu, D., Sampson, A. L., Scott, L. M., Shah, P. D., Shibata, F., Shimodaira, H., Shin, B. K., Shin, J. I., Shirahama, T., Smith, J. D., Sokolsky, P., Sonley, T. J., Springer, R. W., Stokes, B. T., Stratton, S. R., Stroman, T., Suzuki, S., Takahashi, Y., Takita, M., Tanaka, H., Tanaka, K., Tanaka, M., Thomson, G. B., Tinyakov, P., Tkachev, I., Troitsky, S., Tsutsumi, K., Tsuyuguchi, Y., Uchihori, Y., Ukai, H., Vasiloff, G., Wada, Y., Wong, T., Wood, M., Yamakawa, Y., Yamaoka, H., Yamazaki, K., Yang, J., Yoshida, S., Yoshii, H., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Since 2007, the Telescope Array (TA) experiment, based in Utah, USA, has been observing ultra high energy cosmic rays to understand their origins. The experiment involves a surface detector (SD) array and three fluorescence detector (FD) stations. FD stations, installed surrounding the SD array, measure the air fluorescence light emitted from extensive air showers (EASs) for precise determination of their energies and species. The detectors employed at one of the three FD stations were relocated from the High Resolution Fly's Eye experiment. At the other two stations, newly designed detectors were constructed for the TA experiment. An FD consists of a primary mirror and a camera equipped with photomultiplier tubes. To obtain the EAS parameters with high accuracies, understanding the FD optical characteristics is important. In this paper, we report the characteristics and installation of new FDs and the performances of the FD components. The results of the monitored mirror reflectance during the observation time are also described in this report., Comment: 44 pages, 23 figures, submitted to NIM-A

Published
2011
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20. Surface Majorana Cone of the Superfluid $^3$He B Phase

Author

Murakawa, S., Wada, Y., Tamura, Y., Wasai, M., Saitoh, M., Aoki, Y., Nomura, R., Okuda, Y., Nagato, Y., Yamamoto, M., Higashitani, S., and Nagai, K.

Subjects
Condensed Matter - Other Condensed Matter, Condensed Matter - Materials Science
Abstract

The superfluid $^3$He B phase, one of the oldest unconventional fermionic condensates experimentally realized, is recently predicted to support Majorana fermion surface states. Majorana fermion, which is characterized by the equivalence of particle and antiparticle, has a linear dispersion relation referred to as the Majorana cone. We measured the transverse acoustic impedance $Z$ of the superfluid$^3$He B phase changing its boundary condition and found a growth of peak in $Z$ on a higher specularity wall. Our theoretical analysis indicates that the variation of $Z$ is induced by the formation of the cone-like dispersion relation and thus confirms the important feature of the Majorana fermion in the specular limit., Comment: 9pages, 4 figures, to be published in the Journal of Physical Society of Japan, Vol.80, No.1 (2011)

Published
2010
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21. Probing the DeltaNN component of 3He

Author

Huber, G. M., Lolos, G. J., Brash, E. J., Dumalski, S., Farzanpay, F., Iurescu, M., Papandreou, Z., Shinozaki, A., Weinerman, A., Emura, T., Hirosawa, H., Niwa, K., Yamashita, H., Maeda, K., Terasawa, T., Yamazaki, H., Endo, S., Miyamoto, K., Sumi, Y., Garino, G., Maruyama, K., Leone, A., Perrino, R., Maki, T., Sasaki, A., and Wada, Y.

Subjects
Nuclear Experiment
Abstract

The 3He(gamma,pi^+/- p) reactions were measured simultaneously over a tagged photon energy range of 800

Published
1999
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22. Water Scarcity Hotspots Travel Downstream Due to Human Interventions in the 20th and 21st Century

Author

Veldkamp, T. I. E, Wada, Y, Aerts, J. C. J. H, Doell, P, Gosling, S. N, Liu, J, Masaki, Y, Oki, T, Ostberg, S, Pokhrel, Y, Satoh, Y, Kim, H, and Ward, P. J

Subjects
Earth Resources And Remote Sensing
Abstract

Water scarcity is rapidly increasing in many regions. In a novel, multi-model assessment, we examine how human interventions (HI: land use and land cover change, man-made reservoirs and human water use) affected monthly river water availability and water scarcity over the period 1971 - 2010. Here we show that HI drastically change the critical dimensions of water scarcity, aggravating water scarcity for 8.8%(7.4 - 16.5 %) ) of the global population but alleviating it for another 8.3 % (6.4 -15.8 %). Positive impacts of HI mostly occur upstream, whereas HI aggravate water scarcity downstream; HI cause water scarcity to travel downstream. Attribution of water scarcity changes to HI components is complex and varies among the hydrological models. Seasonal variation in impacts and dominant HI components is also substantial. A thorough consideration of the spatially and temporally varying interactions among HI components and of uncertainties is therefore crucial for the success of water scarcity adaptation by HI.

Published
2017
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23. Cross - Scale Intercomparison of Climate Change Impacts Simulated by Regional and Global Hydrological Models in Eleven Large River Basins

Author

Hattermann, F. F, Krysanova, V, Gosling, S. N, Dankers, R, Daggupati, P, Donnelly, C, Florke, M, Huang, S, Motovilov, Y, Buda, S, and Wada, Y

Subjects
Meteorology And Climatology
Abstract

Ideally, the results from models operating at different scales should agree in trend direction and magnitude of impacts under climate change. However, this implies that the sensitivity to climate variability and climate change is comparable for impact models designed for either scale. In this study, we compare hydrological changes simulated by 9 global and 9 regional hydrological models (HM) for 11 large river basins in all continents under reference and scenario conditions. The foci are on model validation runs, sensitivity of annual discharge to climate variability in the reference period, and sensitivity of the long-term average monthly seasonal dynamics to climate change. One major result is that the global models, mostly not calibrated against observations, often show a considerable bias in mean monthly discharge, whereas regional models show a better reproduction of reference conditions. However, the sensitivity of the two HM ensembles to climate variability is in general similar. The simulated climate change impacts in terms of long-term average monthly dynamics evaluated for HM ensemble medians and spreads show that the medians are to a certain extent comparable in some cases, but have distinct differences in other cases, and the spreads related to global models are mostly notably larger. Summarizing, this implies that global HMs are useful tools when looking at large-scale impacts of climate change and variability. Whenever impacts for a specific river basin or region are of interest, e.g. for complex water management applications, the regional-scale models calibrated and validated against observed discharge should be used.

Published
2017
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24. Multi-Model Assessment of Global Hydropower and Cooling Water Discharge Potential Under Climate Change

Author

van Vliet, M. T. H, van Beek, L. P. H, Eisener, S, Wada, Y, and Bierkens, M. F. P

Subjects
Meteorology And Climatology
Abstract

Worldwide, 98% of total electricity is currently produced by thermoelectric power and hydropower. Climate change is expected to directly impact electricity supply, in terms of both water availability for hydropower generation and cooling water usage for thermoelectric power. Improved understanding of how climate change may impact the availability and temperature of water resources is therefore of major importance. Here we use a multi-model ensemble to show the potential impacts of climate change on global hydropower and cooling water discharge potential. For the first time, combined projections of streamflow and water temperature were produced with three global hydrological models (GHMs) to account for uncertainties in the structure and parametrization of these GHMs in both water availability and water temperature. The GHMs were forced with bias-corrected output of five general circulation models (GCMs) for both the lowest and highest representative concentration pathways (RCP2.6 and RCP8.5). The ensemble projections of streamflow and water temperature were then used to quantify impacts on gross hydropower potential and cooling water discharge capacity of rivers worldwide. We show that global gross hydropower potential is expected to increase between +2.4% (GCM-GHM ensemble mean for RCP 2.6) and +6.3% (RCP 8.5) for the 2080s compared to 1971-2000. The strongest increases in hydropower potential are expected for Central Africa, India, central Asia and the northern high-latitudes, with 18-33% of the world population living in these areas by the 2080s. Global mean cooling water discharge capacity is projected to decrease by 4.5-15% (2080s). The largest reductions are found for the United States, Europe, eastern Asia, and southern parts of South America, Africa and Australia, where strong water temperature increases are projected combined with reductions in mean annual streamflow. These regions are expected to affect 11-14% (for RCP2.6 and the shared socioeconomic pathway (SSP)1, SSP2, SSP4) and 41-51% (RCP8.5-SSP3, SSP5) of the world population by the 2080s.

Published
2016
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25. Towards a Global Water Scarcity Risk Assessment Framework: Incorporation of Probability Distributions and Hydro-Climatic Variability

Author

Veldkamp, T. I. E, Wada, Y, Aerts, J. C. J. H, and Ward, P. J

Subjects
Meteorology And Climatology
Abstract

Changing hydro-climatic and socioeconomic conditions increasingly put pressure on fresh water resources and are expected to aggravate water scarcity conditions towards the future. Despite numerous calls for risk-based water scarcity assessments, a global-scale framework that includes UNISDR's definition of risk does not yet exist. This study provides a first step towards such a risk based assessment, applying a Gamma distribution to estimate water scarcity conditions at the global scale under historic and future conditions, using multiple climate change and population growth scenarios. Our study highlights that water scarcity risk, expressed in terms of expected annual exposed population, increases given all future scenarios, up to greater than 56.2% of the global population in 2080. Looking at the drivers of risk, we find that population growth outweigh the impacts of climate change at global and regional scales. Using a risk-based method to assess water scarcity, we show the results to be less sensitive than traditional water scarcity assessments to the use of fixed threshold to represent different levels of water scarcity. This becomes especially important when moving from global to local scales, whereby deviations increase up to 50% of estimated risk levels.

Published
2016
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26. Modeling Global Water Use for the 21st Century: Water Futures and Solutions (WFaS) Initiative and Its Approaches

Author

Wada, Y, Florke, M, Hanasaki, N, Eisner, S, Fischer, G, Tramberend, S, Satoh, Y, van Vliet, M. T. H, Yillia, P, Ringler, C, Burek, P, and Wiberg, D

Subjects
Earth Resources And Remote Sensing
Abstract

To sustain growing food demand and increasing standard of living, global water use increased by nearly 6 times during the last 100 years, and continues to grow. As water demands get closer and closer to the water availability in many regions, each drop of water becomes increasingly valuable and water must be managed more efficiently and intensively. However, soaring water use worsens water scarcity conditions already prevalent in semi-arid and arid regions, increasing uncertainty for sustainable food production and economic development. Planning for future development and investments requires that we prepare water projections for the future. However, estimations are complicated because the future of the world's waters will be influenced by a combination of environmental, social, economic, and political factors, and there is only limited knowledge and data available about freshwater resources and how they are being used. The Water Futures and Solutions (WFaS) initiative coordinates its work with other ongoing scenario efforts for the sake of establishing a consistent set of new global water scenarios based on the shared socio-economic pathways (SSPs) and the representative concentration pathways (RCPs). The WFaS "fast track" assessment uses three global water models, namely H08, PCR-GLOBWB, and WaterGAP. This study assesses the state of the art for estimating and projecting water use regionally and globally in a consistent manner. It provides an overview of different approaches, the uncertainty, strengths and weaknesses of the various estimation methods, types of management and policy decisions for which the current estimation methods are useful. We also discuss additional information most needed to be able to improve water use estimates and be able to assess a greater range of management options across the water-energy-climate nexus.

Published
2016
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27. Total Land Water Storage Change over 2003 - 2013 Estimated from a Global Mass Budget Approach

Author

Dieng, H. B, Champollion, N, Cazenave, A, Wada, Y, Schrama, E, and Meyssignac, B

Subjects
Meteorology And Climatology
Abstract

We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS (the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to +0.30 +/- 0.18 mm/yr in sea level equivalent. This corresponds to a net decrease of −108 +/- 64 cu km/yr in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology.

Published
2015
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28. Exploring the Potential Impacts of Historic Volcanic Eruptions on the Contemporary Global Food System

Author

Puma, Michael J, Chon, S, and Wada, Y

Subjects
Meteorology And Climatology
Abstract

A better understanding of volcanic impacts on crops is urgently needed, as volcanic eruptions and the associated climate anomalies can cause unanticipated shocks to food production. Such shocks are a major concern given the fragility of the global food system.

Published
2015
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29. Sensitivity of Water Scarcity Events to ENSO-Driven Climate Variability at the Global Scale

Author

Veldkamp, T. I. E, Eisner, S, Wada, Y, Aerts, J. C. J. H, and Ward, P. J

Subjects
Meteorology And Climatology
Abstract

Globally, freshwater shortage is one of the most dangerous risks for society. Changing hydro-climatic and socioeconomic conditions have aggravated water scarcity over the past decades. A wide range of studies show that water scarcity will intensify in the future, as a result of both increased consumptive water use and, in some regions, climate change. Although it is well-known that El Niño- Southern Oscillation (ENSO) affects patterns of precipitation and drought at global and regional scales, little attention has yet been paid to the impacts of climate variability on water scarcity conditions, despite its importance for adaptation planning. Therefore, we present the first global-scale sensitivity assessment of water scarcity to ENSO, the most dominant signal of climate variability. We show that over the time period 1961-2010, both water availability and water scarcity conditions are significantly correlated with ENSO-driven climate variability over a large proportion of the global land area (> 28.1 %); an area inhabited by more than 31.4% of the global population. We also found, however, that climate variability alone is often not enough to trigger the actual incidence of water scarcity events. The sensitivity of a region to water scarcity events, expressed in terms of land area or population exposed, is determined by both hydro-climatic and socioeconomic conditions. Currently, the population actually impacted by water scarcity events consists of 39.6% (CTA: consumption-to-availability ratio) and 41.1% (WCI: water crowding index) of the global population, whilst only 11.4% (CTA) and 15.9% (WCI) of the global population is at the same time living in areas sensitive to ENSO-driven climate variability. These results are contrasted, however, by differences in growth rates found under changing socioeconomic conditions, which are relatively high in regions exposed to water scarcity events. Given the correlations found between ENSO and water availability and scarcity conditions, and the relative developments of water scarcity impacts under changing socioeconomic conditions, we suggest that there is potential for ENSO-based adaptation and risk reduction that could be facilitated by more research on this emerging topic.

Published
2015
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31. Response of Solid He-4 to External Stress: Interdigital Capacitor Solid Level Detector and Optical Interferometer

Author

Fay, J, Wada, Y, Masutomi, R, Elkholy, T, and Kojima, H

Subjects
Electronics And Electrical Engineering
Abstract

Two experiments are being conducted to observe the liquid/solid interface of He-4 near 1 K. Interesting instabilities are expected to occur when the solid is non-hydrostatically stressed. (1)A compact interdigital capacitor is used as a level detector to observe solid He-4 to which stresses are applied externally. The capacitor consists of 38 interlaced 50 m wide and 3.8 mm long gold films separated by 50 m and deposited onto a 5 mm by 5 mm sapphire substrate. The capacitor is placed on one flat end wall of a cylindrical chamber (xx mm diameter and xx mm long). The solid is grown to a known height and a stress is applied by a tubular PZT along the cylindrical axis. The observed small change in height of the solid at the wall is linearly proportional to the applied stress. The solid height decreases under compressive stress but does not change under tensile stress. The response of the solid on compressive stress is consistent with the expected quadratic dependence on strain. (2)Interferometric techniques are being developed for observing the solid He-4 surface profile. A laser light source is brought into the low temperature region via single mode optical fiber. The interference pattern is transmitted back out of the low temperature apparatus via optical fiber bundle. The solid He-4 growth chamber will be equipped with two PZT's such that stress can be applied from orthogonal directions. Orthogonally applied stress is expected to induce surface instability with island-like deformation on a grid pattern. Apparatus design and progress of its construction are described.

Published
2003

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