Isotropy of cosmic rays beyond $10^{20}$ eV favors their heavy mass composition
Abstract
We report an estimation of the injected mass composition of ultra-high energy cosmic rays (UHECRs) at energies higher than 10 EeV. The composition is inferred from an energy-dependent sky distribution of UHECR events observed by the Telescope Array surface detector by comparing it to the Large Scale Structure of the local Universe. In the case of negligible extra-galactic magnetic fields the results are consistent with a relatively heavy injected composition at E ~ 10 EeV that becomes lighter up to E ~ 100 EeV, while the composition at E > 100 EeV is very heavy. The latter is true even in the presence of highest experimentally allowed extra-galactic magnetic fields, while the composition at lower energies can be light if a strong EGMF is present. The effect of the uncertainty in the galactic magnetic field on these results is subdominant.
Keywords
Cite
@article{arxiv.2406.19287,
title = {Isotropy of cosmic rays beyond $10^{20}$ eV favors their heavy mass composition},
author = {Telescope Array Collaboration and R. U. Abbasi and Y. Abe and T. Abu-Zayyad and M. Allen and Y. Arai and R. Arimura and E. Barcikowski and J. W. Belz and D. R. Bergman and S. A. Blake and I. Buckland and B. G. Cheon and M. Chikawa and T. Fujii and K. Fujisue and K. Fujita and R. Fujiwara and M. Fukushima and G. Furlich and N. Globus and R. Gonzalez and W. Hanlon and N. Hayashida and H. He and R. Hibi and K. Hibino and R. Higuchi and K. Honda and D. Ikeda and N. Inoue and T. Ishii and H. Ito and D. Ivanov and A. Iwasaki and H. M. Jeong and S. Jeong and C. C. H. Jui and K. Kadota and F. Kakimoto and O. Kalashev and K. Kasahara and S. Kasami and S. Kawakami and K. Kawata and I. Kharuk and E. Kido and H. B. Kim and J. H. Kim and J. H. Kim and S. W. Kim and Y. Kimura and I. Komae and V. Kuzmin and M. Kuznetsov and Y. J. Kwon and K. H. Lee and B. Lubsandorzhiev and J. P. Lundquist and H. Matsumiya and T. Matsuyama and J. N. Matthews and R. Mayta and K. Mizuno and M. Murakami and I. Myers and K. H. Lee and S. Nagataki and K. Nakai and T. Nakamura and E. Nishio and T. Nonaka and H. Oda and S. Ogio and M. Onishi and H. Ohoka and N. Okazaki and Y. Oku and T. Okuda and Y. Omura and M. Ono and A. Oshima and H. Oshima and S. Ozawa and I. H. Park and K. Y. Park and M. Potts and M. S. Pshirkov and J. Remington and D. C. Rodriguez and C. Rott and G. I. Rubtsov and D. Ryu and H. Sagawa and R. Saito and N. Sakaki and T. Sako and N. Sakurai and D. Sato and K. Sato and S. Sato and K. Sekino and P. D. Shah and N. Shibata and T. Shibata and J. Shikita and H. Shimodaira and B. K. Shin and H. S. Shin and D. Shinto and J. D. Smith and P. Sokolsky and B. T. Stokes and T. A. Stroman and Y. Takagi and K. Takahashi and M. Takamura and M. Takeda and R. Takeishi and A. Taketa and M. Takita and Y. Tameda and K. Tanaka and M. Tanaka and Y. Tanoue and S. B. Thomas and G. B. Thomson and P. Tinyakov and I. Tkachev and H. Tokuno and T. Tomida and S. Troitsky and R. Tsuda and Y. Tsunesada and S. Udo and F. Urban and D. Warren and T. Wong and K. Yamazaki and K. Yashiro and F. Yoshida and Y. Zhezher and Z. Zundel},
journal= {arXiv preprint arXiv:2406.19287},
year = {2024}
}
Comments
8 pages, 3 figures, accepted for publication in PRL