Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

Issued Date

2024-03-29

Resource Type

Article

ISSN

00319007

eISSN

10797114

DOI

10.1103/PhysRevLett.132.131002

Scopus ID

2-s2.0-85188794641

Journal Title

Physical Review Letters

Volume

132

Issue

13

Rights Holder(s)

SCOPUS

Bibliographic Citation

Physical Review Letters Vol.132 No.13 (2024)

Suggested Citation

Cao Z., Aharonian F., Axikegu, Bai Y.X., Bao Y.W., Bastieri D., Bi X.J., Bi Y.J., Bian W., Bukevich A.V., Cao Q., Cao W.Y., Cao Z., Chang J., Chang J.F., Chen A.M., Chen E.S., Chen H.X., Chen L., Chen L., Chen L., Chen M.J., Chen M.L., Chen Q.H., Chen S., Chen S.H., Chen S.Z., Chen T.L., Chen Y., Cheng N., Cheng Y.D., Cui M.Y., Cui S.W., Cui X.H., Cui Y.D., Dai B.Z., Dai H.L., Dai Z.G., Danzengluobu, Dong X.Q., Duan K.K., Fan J.H., Fan Y.Z., Fang J., Fang J.H., Fang K., Feng C.F., Feng H., Feng L., Feng S.H., Feng X.T., Feng Y., Feng Y.L., Gabici S., Gao B., Gao C.D., Gao Q., Gao W., Gao W.K., Ge M.M., Geng L.S., Giacinti G., Gong G.H., Gou Q.B., Gu M.H., Guo F.L., Guo X.L., Guo Y.Q., Guo Y.Y., Han Y.A., Hasan M., He H.H., He H.N., He J.Y., He Y., Hor Y.K., Hou B.W., Hou C., Hou X., Hu H.B., Hu Q., Hu S.C., Huang D.H., Huang T.Q., Huang W.J., Huang X.T., Huang X.Y., Huang Y., Ji X.L., Jia H.Y., Jia K., Jiang K., Jiang X.W., Jiang Z.J., Jin M., Kang M.M., Karpikov I., Kuleshov D., Kurinov K., Li B.B. Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A. Physical Review Letters Vol.132 No.13 (2024). doi:10.1103/PhysRevLett.132.131002 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/97836

Title

Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

Author(s)

Cao Z.
 Aharonian F.
 Axikegu
 Bai Y.X.
 Bao Y.W.
 Bastieri D.
 Bi X.J.
 Bi Y.J.
 Bian W.
 Bukevich A.V.
 Cao Q.
 Cao W.Y.
 Cao Z.
 Chang J.
 Chang J.F.
 Chen A.M.
 Chen E.S.
 Chen H.X.
 Chen L.
 Chen L.
 Chen L.
 Chen M.J.
 Chen M.L.
 Chen Q.H.
 Chen S.
 Chen S.H.
 Chen S.Z.
 Chen T.L.
 Chen Y.
 Cheng N.
 Cheng Y.D.
 Cui M.Y.
 Cui S.W.
 Cui X.H.
 Cui Y.D.
 Dai B.Z.
 Dai H.L.
 Dai Z.G.
 Danzengluobu
 Dong X.Q.
 Duan K.K.
 Fan J.H.
 Fan Y.Z.
 Fang J.
 Fang J.H.
 Fang K.
 Feng C.F.
 Feng H.
 Feng L.
 Feng S.H.
 Feng X.T.
 Feng Y.
 Feng Y.L.
 Gabici S.
 Gao B.
 Gao C.D.
 Gao Q.
 Gao W.
 Gao W.K.
 Ge M.M.
 Geng L.S.
 Giacinti G.
 Gong G.H.
 Gou Q.B.
 Gu M.H.
 Guo F.L.
 Guo X.L.
 Guo Y.Q.
 Guo Y.Y.
 Han Y.A.
 Hasan M.
 He H.H.
 He H.N.
 He J.Y.
 He Y.
 Hor Y.K.
 Hou B.W.
 Hou C.
 Hou X.
 Hu H.B.
 Hu Q.
 Hu S.C.
 Huang D.H.
 Huang T.Q.
 Huang W.J.
 Huang X.T.
 Huang X.Y.
 Huang Y.
 Ji X.L.
 Jia H.Y.
 Jia K.
 Jiang K.
 Jiang X.W.
 Jiang Z.J.
 Jin M.
 Kang M.M.
 Karpikov I.
 Kuleshov D.
 Kurinov K.
 Li B.B.

Author's Affiliation

Zhejiang Lab
 State Key Laboratory of Particle Detection & Electronics
 Université Paris Cité
 Yunnan Observatories
 Nanjing University
 Shanghai Astronomical Observatory Chinese Academy of Sciences
 Institute for Nuclear Research of the Russian Academy of Sciences
 Shandong University
 Yunnan University
 Institute of High Energy Physics, Chinese Academy of Sciences
 University of Chinese Academy of Sciences
 Guangzhou University
 Tsinghua University
 Shanghai Jiao Tong University
 Sun Yat-Sen University
 University of Science and Technology of China
 Zhengzhou University
 Institiúid Ard-Lénn Bhaile Átha Cliath
 Sichuan University
 National Astronomical Observatories Chinese Academy of Sciences
 Max-Planck-Institut für Kernphysik
 Southwest Jiaotong University
 China Center of Advanced Science and Technology World Laboratory
 Purple Mountain Observatory Chinese Academy of Sciences
 Hebei Normal University
 Tibet University
 TIANFU Cosmic Ray Research Center

Corresponding Author(s)

Cao Z.

Other Contributor(s)

Mahidol University

Abstract

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

Keyword(s)

Physics and Astronomy

Availability

URI

https://repository.li.mahidol.ac.th/handle/20.500.14594/97836

Collections

Scopus 2024