Cosmic ray composition studies through the Gerasimova-Zatsepin effects of heavy nuclei at LAAS

Iyono, A.; Matsumoto, H.; Okei, K.; Tsuji, S.; Ohara, S.; Ochi, N.; Konishi, T.; Takahashi, N.; Yamamoto, I.; Nakatsuka, T.; Nakamura, T.; Ohmori, N.; Saitoh, K.

doi:doi:10.5194/astra-7-327-2011

Astrophys. Space Sci. Trans., 7, 327-333, 2011
www.astrophys-space-sci-trans.net/7/327/2011/
doi:10.5194/astra-7-327-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.

Volume 7, issue 3

01 Sep 2011

Cosmic ray composition studies through the Gerasimova-Zatsepin effects of heavy nuclei at LAAS
A. Iyono¹, H. Matsumoto¹, K. Okei², S. Tsuji², S. Ohara³, N. Ochi⁴, T. Konishi⁵, N. Takahashi⁶, I. Yamamoto⁷, T. Nakatsuka⁸, T. Nakamura⁹, N. Ohmori⁹, and K. Saitoh¹⁰
¹Dept. of Fundamental Science, Okayama University of Science, Okayama 700-0005, Japan
²Kawasaki Medical School, Kurashiki 701-0192, Japan
³Nara University of Industry, Nara 636-8503, Japan
⁴Yonago National College of Technology, Tottori 683-8502, Japan
⁵Kinki University, Osaka 577-8502, Japan
⁶Hirosaki University, Hirosaki 036-8561, Japan
⁷Dept. of Information and Computer Engineering, Okayama University of Science, Okayama 700-0005, Japan
⁸Okayama Shoka University, Okayama 700-8601, Japan
⁹Kochi University, Kochi 780-8520, Japan
¹⁰Ashikaga Institute of Technology, Ashikaga 326-8558, Japan

Received: 14 Nov 2010 – Revised: 01 Mar 2011 – Accepted: 23 Mar 2011 – Published: 01 Sep 2011

Abstract. Extensive air showers (EASs) originated from primary cosmic ray energies above 10¹⁵ eV have been measured at multiple EAS observatories deployed in Japan since Sept. 1996. The typical EAS array has been located at the rooftop of the buildings in the university campus, and has GPS-disciplined 10 MHz oscillator to provide the UTC time stamp for each EAS event within a few μs accuracies. Searching for simultaneous and parallel EAS events at multiple EAS observatories due to Gerasimova-Zatsepin (GZ) effects have been carried out by comparing EAS arrival time stamps and directions detected by several baseline combinations of EAS arrays.

The EAS pairs whose time difference and angular distance were less than 5 ms and less than 15° respectively, were selected and their angular distances from the solar direction and the lunar direction were examined. The data were compared with numerical GZ probability as a function of arrival directions of cosmic ray nuclei. Consequently, significant excesses of these events in the solar direction as expected in the numerical prediction of GZ effects were not found. We however found that the deficiencies of EAS pairs in the lunar direction, but its deviation is not significant.

Citation: Iyono, A., Matsumoto, H., Okei, K., Tsuji, S., Ohara, S., Ochi, N., Konishi, T., Takahashi, N., Yamamoto, I., Nakatsuka, T., Nakamura, T., Ohmori, N., and Saitoh, K.: Cosmic ray composition studies through the Gerasimova-Zatsepin effects of heavy nuclei at LAAS, Astrophys. Space Sci. Trans., 7, 327-333, doi:10.5194/astra-7-327-2011, 2011.

Astrophysics and Space Sciences Transactions

An Open Access Journal of the Arbeitsgemeinschaft Extraterrestrische Forschung e.V.