Are protons still dominant at the knee of the cosmic-ray energy spectrum?

M. Amenomori; S. Ayabe; D. Chen; S. W. Cui; Danzengluobu; L. K. Ding; X. H. Ding; C. F. Feng; Z. Y. Feng; X. Y. Gao; Q. X. Geng; H. W. Guo; H. H. He; M. He; K. Hibino; N. Hotta; Haibing Hu; H. B. Hu; J. Huang; Q. Huang; H. Y. Jia; F. Kajino; K. Kasahara; Y. Katayose; C. Kato; K. Kawata; Labaciren; G. M. Le; J. Y. Li; H. Lu; S. L. Lu; X. R. Meng; K. Mizutani; J. Mu; K. Munakata; A. Nagai; H. Nanjo; M. Nishizawa; M. Ohnishi; I. Ohta; H. Onuma; T. Ouchi; Shunsuke Ozawa; J. R. Ren; T. Saito; M. Sakata; T. Sasaki; M. Shibata; A. Shiomi; T. Shirai; H. Sugimoto; M. Takita; Y. H. Tan; N. Tateyama; Shoji Torii; H. Tsuchiya; S. Udo; H. Wang; X. Wang; Y. G. Wang; H. R. Wu; L. Xue; Y. Yamamoto; C. T. Yan; X. C. Yang; S. Yasue; Z. H. Ye; G. C. Yu; A. F. Yuan; T. Yuda; H. M. Zhang; J. L. Zhang; N. J. Zhang; X. Y. Zhang; Y. Zhang; Yi Zhang; Zhaxisangzhu; X. X. Zhou

doi:10.1016/j.physletb.2005.10.048

Are protons still dominant at the knee of the cosmic-ray energy spectrum?

M. Amenomori, S. Ayabe, D. Chen, S. W. Cui, Danzengluobu, L. K. Ding, X. H. Ding, C. F. Feng, Z. Y. Feng, X. Y. Gao, Q. X. Geng, H. W. Guo, H. H. He, M. He, K. Hibino, N. Hotta, Haibing Hu, H. B. Hu, J. Huang^*, Q. HuangH. Y. Jia, F. Kajino, K. Kasahara, Y. Katayose, C. Kato, K. Kawata, Labaciren, G. M. Le, J. Y. Li, H. Lu, S. L. Lu, X. R. Meng, K. Mizutani, J. Mu, K. Munakata, A. Nagai, H. Nanjo, M. Nishizawa, M. Ohnishi, I. Ohta, H. Onuma, T. Ouchi, Shunsuke Ozawa, J. R. Ren, T. Saito, M. Sakata, T. Sasaki, M. Shibata, A. Shiomi, T. Shirai, H. Sugimoto, M. Takita, Y. H. Tan, N. Tateyama, Shoji Torii, H. Tsuchiya, S. Udo, H. Wang, X. Wang, Y. G. Wang, H. R. Wu, L. Xue, Y. Yamamoto, C. T. Yan, X. C. Yang, S. Yasue, Z. H. Ye, G. C. Yu, A. F. Yuan, T. Yuda, H. M. Zhang, J. L. Zhang, N. J. Zhang, X. Y. Zhang, Y. Zhang, Yi Zhang, Zhaxisangzhu, X. X. Zhou

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

123 Citations (Scopus)

Abstract

A hybrid experiment consisting of emulsion chambers, burst detectors and the Tibet-II air-shower array was carried out at Yangbajing (4300 m a.s.l., 606 g/cm2) in Tibet to obtain the energy spectra of primary protons and heliums. From three-year operation, these energy spectra are deduced between 10 ¹⁵ and 1016 eV by triggering the air showers associated with a high energy core and using a neural network method in the primary mass separation. The proton spectrum can be expressed by a single power-law function with a differential index of -3.01±0.11 and -3.05±0.12 based on the QGSJET + HD and SIBYLL + HD models, respectively, which are steeper than that extrapolated from the direct observations of -2.74±0.01 in the energy range below 1014 eV. The absolute fluxes of protons and heliums are derived within 30% systematic errors depending on the hadronic interaction models used in Monte Carlo simulation. The result of our experiment suggests that the main component responsible for the change of the power index of the all-particle spectrum around 3×1015 eV, so-called "knee", is composed of nuclei heavier than helium. This is the first measurement of the differential energy spectra of primary protons and heliums by selecting them event by event at the knee energy region.

Original language	English
Pages (from-to)	58-64
Number of pages	7
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	632
Issue number	1
DOIs	https://doi.org/10.1016/j.physletb.2005.10.048
Publication status	Published - 2006 Jan 5

Keywords

γ-family
Cosmic rays
Knee energy region
Neural network
Proton

ASJC Scopus subject areas

Nuclear and High Energy Physics

Access to Document

10.1016/j.physletb.2005.10.048

Cite this

Amenomori, M., Ayabe, S., Chen, D., Cui, S. W., Danzengluobu, Ding, L. K., Ding, X. H., Feng, C. F., Feng, Z. Y., Gao, X. Y., Geng, Q. X., Guo, H. W., He, H. H., He, M., Hibino, K., Hotta, N., Hu, H., Hu, H. B., Huang, J., ... Zhou, X. X. (2006). Are protons still dominant at the knee of the cosmic-ray energy spectrum? Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 632(1), 58-64. https://doi.org/10.1016/j.physletb.2005.10.048

Amenomori, M, Ayabe, S, Chen, D, Cui, SW, Danzengluobu, Ding, LK, Ding, XH, Feng, CF, Feng, ZY, Gao, XY, Geng, QX, Guo, HW, He, HH, He, M, Hibino, K, Hotta, N, Hu, H, Hu, HB, Huang, J, Huang, Q, Jia, HY, Kajino, F, Kasahara, K, Katayose, Y, Kato, C, Kawata, K, Labaciren, Le, GM, Li, JY, Lu, H, Lu, SL, Meng, XR, Mizutani, K, Mu, J, Munakata, K, Nagai, A, Nanjo, H, Nishizawa, M, Ohnishi, M, Ohta, I, Onuma, H, Ouchi, T, Ozawa, S, Ren, JR, Saito, T, Sakata, M, Sasaki, T, Shibata, M, Shiomi, A, Shirai, T, Sugimoto, H, Takita, M, Tan, YH, Tateyama, N, Torii, S, Tsuchiya, H, Udo, S, Wang, H, Wang, X, Wang, YG, Wu, HR, Xue, L, Yamamoto, Y, Yan, CT, Yang, XC, Yasue, S, Ye, ZH, Yu, GC, Yuan, AF, Yuda, T, Zhang, HM, Zhang, JL, Zhang, NJ, Zhang, XY, Zhang, Y, Zhang, Y, Zhaxisangzhu & Zhou, XX 2006, 'Are protons still dominant at the knee of the cosmic-ray energy spectrum?', Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 632, no. 1, pp. 58-64. https://doi.org/10.1016/j.physletb.2005.10.048

@article{8d623fac131d48c885c8d3063cc621a3,

title = "Are protons still dominant at the knee of the cosmic-ray energy spectrum?",

abstract = "A hybrid experiment consisting of emulsion chambers, burst detectors and the Tibet-II air-shower array was carried out at Yangbajing (4300 m a.s.l., 606 g/cm2) in Tibet to obtain the energy spectra of primary protons and heliums. From three-year operation, these energy spectra are deduced between 10 15 and 1016 eV by triggering the air showers associated with a high energy core and using a neural network method in the primary mass separation. The proton spectrum can be expressed by a single power-law function with a differential index of -3.01±0.11 and -3.05±0.12 based on the QGSJET + HD and SIBYLL + HD models, respectively, which are steeper than that extrapolated from the direct observations of -2.74±0.01 in the energy range below 1014 eV. The absolute fluxes of protons and heliums are derived within 30% systematic errors depending on the hadronic interaction models used in Monte Carlo simulation. The result of our experiment suggests that the main component responsible for the change of the power index of the all-particle spectrum around 3×1015 eV, so-called {"}knee{"}, is composed of nuclei heavier than helium. This is the first measurement of the differential energy spectra of primary protons and heliums by selecting them event by event at the knee energy region.",

keywords = "γ-family, Cosmic rays, Knee energy region, Neural network, Proton",

author = "M. Amenomori and S. Ayabe and D. Chen and Cui, {S. W.} and Danzengluobu and Ding, {L. K.} and Ding, {X. H.} and Feng, {C. F.} and Feng, {Z. Y.} and Gao, {X. Y.} and Geng, {Q. X.} and Guo, {H. W.} and He, {H. H.} and M. He and K. Hibino and N. Hotta and Haibing Hu and Hu, {H. B.} and J. Huang and Q. Huang and Jia, {H. Y.} and F. Kajino and K. Kasahara and Y. Katayose and C. Kato and K. Kawata and Labaciren and Le, {G. M.} and Li, {J. Y.} and H. Lu and Lu, {S. L.} and Meng, {X. R.} and K. Mizutani and J. Mu and K. Munakata and A. Nagai and H. Nanjo and M. Nishizawa and M. Ohnishi and I. Ohta and H. Onuma and T. Ouchi and Shunsuke Ozawa and Ren, {J. R.} and T. Saito and M. Sakata and T. Sasaki and M. Shibata and A. Shiomi and T. Shirai and H. Sugimoto and M. Takita and Tan, {Y. H.} and N. Tateyama and Shoji Torii and H. Tsuchiya and S. Udo and H. Wang and X. Wang and Wang, {Y. G.} and Wu, {H. R.} and L. Xue and Y. Yamamoto and Yan, {C. T.} and Yang, {X. C.} and S. Yasue and Ye, {Z. H.} and Yu, {G. C.} and Yuan, {A. F.} and T. Yuda and Zhang, {H. M.} and Zhang, {J. L.} and Zhang, {N. J.} and Zhang, {X. Y.} and Y. Zhang and Yi Zhang and Zhaxisangzhu and Zhou, {X. X.}",

year = "2006",

month = jan,

day = "5",

doi = "10.1016/j.physletb.2005.10.048",

language = "English",

volume = "632",

pages = "58--64",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",