1205.5067 (T. Abu-Zayyad et al.)

The Cosmic Ray Energy Spectrum Observed with the Surface Detector of the Telescope Array Experiment    [PDF]

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

The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays for energies above 1.6x10^(18) eV in its first three years of operation. The spectrum shows a dip at an energy of 5x10^(18) eV and a steepening at 5x10^(19) eV which is consistent with the expectation from the GZK cutoff. Here we use a new technique that involves generating a complete simulation of 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.

View original: http://arxiv.org/abs/1205.5067