Knee of the cosmic hydrogen and helium spectrum below 1 PeV measured by ARGO-YBJ and a Cherenkov telescope of LHAASO

Bartoli, B.; Bernardini, P.; X. J., Bi; Cao, Z.; Catalanotti, S.; Chen, S. Z.; Chen, T. L.; Cui, S. W.; Dai, B. Z.; D'Amone, A.; Danzengluobu, Null; De Mitri, I.; D'Ettorre Piazzoli, B.; Di Girolamo, T.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Guo, Q. B.; Guo, Y. Q.; H. H., He; Haibing, Hu; Hongbo, Hu; Iacovacci, M.; Iuppa, R.; Jia, H. Y.; Labaciren, Null; H. J., Li; Liu, C.; Liu, J.; Liu, M. Y.; Lu, H.; L. L., Ma; X. H., Ma; Mancarella, G.; Mari, S. M.; Marsella, G.; Mastroianni, S.; Montini, P.; Ning, C. C.; Perrone, L.; Pistilli, P.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, H.; C. Y., Wu; H. R., Wu; Xue, L.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, L.; Zhang, X. Y.; Zhang, Y.; Zhao, J.; Zhaxiciren, Null; Zhaxisangzhu, Null; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Bai, Y. X.; Chen, M. J.; Feng, S. H.; Gao, B.; M. H., Gu; Hou, C.; Liu, J.; Liu, J. L.; Wang, X.; Xiao, G.; Zhang, B. K.; Zhang, S. S.; Zhou, B.; Zuo, X.

doi:10.1103/PhysRevD.92.092005

The measurement of the cosmic ray energy spectrum, in particular for individual species of nuclei, is an important tool to investigate cosmic ray production and propagation mechanisms. The determination of the “knees” in the spectra of different species remains one of the main challenges in cosmic ray physics. In fact, experimental results are still conflicting. In this paper we report a measurement of the mixed proton and helium energy spectrum, obtained with the combined data of the ARGO-YBJ experiment and a wide field of view Cherenkov telescope, a prototype of the future LHAASO experiment.