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

Abstract

Extensive air showers (EASs) originated from primary cosmic ray energies above 10<sup>15</sup> 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. <br><br> 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

The primary energy spectrum with the Linsley method correcting heavy primary effects in the LAAS experiments

“…The primary energy spectrum is updated in this work, α proton and α iron are equal to −2.46 ± 0.17 and −3.08 ± 0.24, respectively, in the primary energy region of 10 16 eV − 10 18. 5 Figure 5. The data spectrum assumed to be proton and iron primaries, respectively, in the OUS1 (A), and in the OUS1+4 (B).…”

“…The Large Area Air Shower (LAAS) experiments [1,2] have been observing cosmic rays with compact Extensive Air Shower (EAS) arrays, and have maintained EAS arrays at several institutes since 1996. The purposes of LAAS experiments are to study the primary energy spectrum, anisotropy of high energy cosmic rays, and simultaneous and parallel EAS events [3][4][5][6][7]. The group of Okayama University of Science has mainly observed cosmic rays in the primary energy range above 10 15 eV and studied its primary energy spectrum.…”

Looking for long-range correlations among the EEE telescopes

“…To date, no certain evidence of these mechanisms has been experimentally confirmed, possibly owing to the limitations of existing observational technology. In the past, the LAAS [11][12][13] and ALTA/CZELTA [14,15] Collaborations have reported on preliminary large-scale coincidences between extensive air showers, whereas other detector networks, employing a large variety of technologies, are currently performing campaigns to detect simultaneous showers. In this scenario the EEE Project [16] has built a sparse array of cosmic ray telescopes, spread over the Italian territory, with the ambitious goal of looking for long-range correlations between EASs.…”

“…M. Abbrescia 1,2 , C. Avanzini 3 , L. Baldini 3,4 , R. Baldini Ferroli 5 , G. Batignani 3,4 , M. Battaglieri 6,7 , S. Boi 8,9 , E. Bossini 3,4 , F. Carnesecchi 10,11 , C. Cicalò 9 , L. Cifarelli 10,11 , F. Coccetti 12 , E. Coccia 13 , A. Corvaglia 14 , D. De Gruttola 15,16 , S. De Pasquale 15,16 , F. Fabbri 5 , L. Galante 17,18 , M. Garbini 10,12 , G. Gemme 6 , I. Gnesi 12,19 , S. Grazzi 6,20 , D. Hatzifotiadou 10,21 , P. La Rocca 22,23…”

The primary energy spectrum with the Linsley method correcting heavy primary effects in the LAAS experiments

“…The purposes of LAAS experiments are to study the primary energy spectrum, anisotropy of high energy cosmic rays, and simultaneous and parallel EAS events [3][4][5][6][7]. The group of Okayama University of Science has mainly observed cosmic rays in the primary energy range above 10 15 eV and studied its primary energy spectrum.…”