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

Zhen Cao^{1

2

3}, F Aharonian^{4

5}, Axikegu⁶, Y X Bai^{1

3}, Y W Bao⁷, D Bastieri⁸, X J Bi^{1

2

3}, Y J Bi^{1

3}, W Bian⁹, A V Bukevich¹⁰, Q Cao¹¹, W Y Cao¹², Zhe Cao^{12

13}, J Chang¹⁴, J F Chang^{1

3

13}, A M Chen⁹, E S Chen^{1

2

3}, H X Chen¹⁵, Liang Chen¹⁶, Lin Chen⁶, Long Chen⁶, M J Chen^{1

3}, M L Chen^{1

3

13}, Q H Chen⁶, S Chen¹⁷, S H Chen^{1

2

3}, S Z Chen^{1

3}, T L Chen¹⁸, Y Chen⁷, N Cheng^{1

3}, Y D Cheng^{1

2

3}, M Y Cui¹⁴, S W Cui¹¹, X H Cui¹⁹, Y D Cui²⁰, B Z Dai¹⁷, H L Dai^{1

3

13}, Z G Dai¹², Danzengluobu¹⁸, X Q Dong^{1

2

3}, K K Duan¹⁴, J H Fan⁸, Y Z Fan¹⁴, J Fang¹⁷, J H Fang¹⁵, K Fang^{1

3}, C F Feng²¹, H Feng¹, L Feng¹⁴, S H Feng^{1

3}, X T Feng²¹, Y Feng¹⁵, Y L Feng¹⁸, S Gabici²², B Gao^{1

3}, C D Gao²¹, Q Gao¹⁸, W Gao^{1

3}, W K Gao^{1

2

3}, M M Ge¹⁷, L S Geng^{1

3}, G Giacinti⁹, G H Gong²³, Q B Gou^{1

3}, M H Gu^{1

3

13}, F L Guo¹⁶, X L Guo⁶, Y Q Guo^{1

3}, Y Y Guo¹⁴, Y A Han²⁴, M Hasan^{1

2

3}, H H He^{1

2

3}, H N He¹⁴, J Y He¹⁴, Y He⁶, Y K Hor²⁰, B W Hou^{1

2

3}, C Hou^{1

3}, X Hou²⁵, H B Hu^{1

2

3}, Q Hu^{12

14}, S C Hu^{1

3

26}, D H Huang⁶, T Q Huang^{1

3}, W J Huang²⁰, X T Huang²¹, X Y Huang¹⁴, Y Huang^{1

2

3}, X L Ji^{1

3

13}, H Y Jia⁶, K Jia²¹, K Jiang^{12

13}, X W Jiang^{1

3}, Z J Jiang¹⁷, M Jin⁶, M M Kang²⁷, I Karpikov¹⁰, D Kuleshov¹⁰, K Kurinov¹⁰, B B Li¹¹, C M Li⁷, Cheng Li^{12

13}, Cong Li^{1

3}, D Li^{1

2

3}, F Li^{1

3

13}, H B Li^{1

3}, H C Li^{1

3}, Jian Li¹², Jie Li^{1

3

13}, K Li^{1

3}, S D Li^{2

16}, W L Li²¹, W L Li⁹, X R Li^{1

3}, Xin Li^{12

13}, Y Z Li^{1

2

3}, Zhe Li^{1

3}, Zhuo Li²⁸, E W Liang²⁹, Y F Liang²⁹, S J Lin²⁰, B Liu¹², C Liu^{1

3}, D Liu²¹, D B Liu⁹, H Liu⁶, H D Liu²⁴, J Liu^{1

3}, J L Liu^{1

3}, M Y Liu¹⁸, R Y Liu⁷, S M Liu⁶, W Liu^{1

3}, Y Liu⁸, Y N Liu²³, Q Luo²⁰, Y Luo⁹, H K Lv^{1

3}, B Q Ma²⁸, L L Ma^{1

3}, X H Ma^{1

3}, J R Mao²⁵, Z Min^{1

3}, W Mitthumsiri³⁰, H J Mu²⁴, Y C Nan^{1

3}, A Neronov²², L J Ou⁸, P Pattarakijwanich³⁰, Z Y Pei⁸, J C Qi^{1

2

3}, M Y Qi^{1

3}, B Q Qiao^{1

3}, J J Qin¹², A Raza^{1

2

3}, D Ruffolo³⁰, A Sáiz³⁰, M Saeed^{1

2

3}, D Semikoz²², L Shao¹¹, O Shchegolev^{10

31}, X D Sheng^{1

3}, F W Shu³², H C Song²⁸, Yu V Stenkin^{10

31}, V Stepanov¹⁰, Y Su¹⁴, D X Sun^{12

14}, Q N Sun⁶, X N Sun²⁹, Z B Sun³³, J Takata³⁴, P H T Tam²⁰, Q W Tang³², R Tang⁹, Z B Tang^{12

13}, W W Tian^{2

19}, C Wang³³, C B Wang⁶, G W Wang¹², H G Wang⁸, H H Wang²⁰, J C Wang²⁵, Kai Wang⁷, Kai Wang³⁴, L P Wang^{1

2

3}, L Y Wang^{1

3}, P H Wang⁶, R Wang²¹, W Wang²⁰, X G Wang²⁹, X Y Wang⁷, Y Wang⁶, Y D Wang^{1

3}, Y J Wang^{1

3}, Z H Wang²⁷, Z X Wang¹⁷, Zhen Wang⁹, Zheng Wang^{1

3

13}, D M Wei¹⁴, J J Wei¹⁴, Y J Wei^{1

2

3}, T Wen¹⁷, C Y Wu^{1

3}, H R Wu^{1

3}, Q W Wu³⁴, S Wu^{1

3}, X F Wu¹⁴, Y S Wu¹², S Q Xi^{1

3}, J Xia^{12

14}, G M Xiang^{2

16}, D X Xiao¹¹, G Xiao^{1

3}, Y L Xin⁶, Y Xing¹⁶, D R Xiong²⁵, Z Xiong^{1

2

3}, D L Xu⁹, R F Xu^{1

2

3}, R X Xu²⁸, W L Xu²⁷, L Xue²¹, D H Yan¹⁷, J Z Yan¹⁴, T Yan^{1

3}, C W Yang²⁷, C Y Yang²⁵, F Yang¹¹, F F Yang^{1

3

13}, L L Yang²⁰, M J Yang^{1

3}, R Z Yang¹², W X Yang⁸, Y H Yao^{1

3}, Z G Yao^{1

3}, L Q Yin^{1

3}, N Yin²¹, X H You^{1

3}, Z Y You^{1

3}, Y H Yu¹², Q Yuan¹⁴, H Yue^{1

2

3}, H D Zeng¹⁴, T X Zeng^{1

3

13}, W Zeng¹⁷, M Zha^{1

3}, B B Zhang⁷, F Zhang⁶, H Zhang⁹, H M Zhang⁷, H Y Zhang^{1

3}, J L Zhang¹⁹, Li Zhang¹⁷, P F Zhang¹⁷, P P Zhang^{12

14}, R Zhang^{12

14}, S B Zhang^{2

19}, S R Zhang¹¹, S S Zhang^{1

3}, X Zhang⁷, X P Zhang^{1

3}, Y F Zhang⁶, Yi Zhang^{1

14}, Yong Zhang^{1

3}, B Zhao⁶, J Zhao^{1

3}, L Zhao^{12

13}, L Z Zhao¹¹, S P Zhao¹⁴, X H Zhao²⁵, F Zheng³³, W J Zhong⁷, B Zhou^{1

3}, H Zhou⁹, J N Zhou¹⁶, M Zhou³², P Zhou⁷, R Zhou²⁷, X X Zhou^{1

2

3}, X X Zhou⁶, B Y Zhu^{12

14}, C G Zhu²¹, F R Zhu⁶, H Zhu¹⁹, K J Zhu^{1

2

3

13}, Y C Zou³⁴, X Zuo^{1

3}; LHAASO Collaboration

Affiliations

¹ Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.
² University of Chinese Academy of Sciences, 100049 Beijing, China.
³ Tianfu Cosmic Ray Research Center, 610000 Chengdu, Sichuan, China.
⁴ Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, 2 Dublin, Ireland.
⁵ Max-Planck-Institut for Nuclear Physics, P.O. Box 103980, 69029 Heidelberg, Germany.
⁶ School of Physical Science and Technology and School of Information Science and Technology, Southwest Jiaotong University, 610031 Chengdu, Sichuan, China.
⁷ School of Astronomy and Space Science, Nanjing University, 210023 Nanjing, Jiangsu, China.
⁸ Center for Astrophysics, Guangzhou University, 510006 Guangzhou, Guangdong, China.
⁹ Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong University, 200240 Shanghai, China.
¹⁰ Institute for Nuclear Research of Russian Academy of Sciences, 117312 Moscow, Russia.
¹¹ Hebei Normal University, 050024 Shijiazhuang, Hebei, China.
¹² University of Science and Technology of China, 230026 Hefei, Anhui, China.
¹³ State Key Laboratory of Particle Detection and Electronics, China.
¹⁴ Key Laboratory of Dark Matter and Space Astronomy and Key Laboratory of Radio Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, 210023 Nanjing, Jiangsu, China.
¹⁵ Research Center for Astronomical Computing, Zhejiang Laboratory, 311121 Hangzhou, Zhejiang, China.
¹⁶ Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 200030 Shanghai, China.
¹⁷ School of Physics and Astronomy, Yunnan University, 650091 Kunming, Yunnan, China.
¹⁸ Key Laboratory of Cosmic Rays (Tibet University), Ministry of Education, 850000 Lhasa, Tibet, China.
¹⁹ National Astronomical Observatories, Chinese Academy of Sciences, 100101 Beijing, China.
²⁰ School of Physics and Astronomy (Zhuhai) and School of Physics (Guangzhou) and Sino-French Institute of Nuclear Engineering and Technology (Zhuhai), Sun Yat-sen University, 519000 Zhuhai and 510275 Guangzhou, Guangdong, China.
²¹ Institute of Frontier and Interdisciplinary Science, Shandong University, 266237 Qingdao, Shandong, China.
²² APC, Université Paris Cité, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, 119 75205 Paris, France.
²³ Department of Engineering Physics, Tsinghua University, 100084 Beijing, China.
²⁴ School of Physics and Microelectronics, Zhengzhou University, 450001 Zhengzhou, Henan, China.
²⁵ Yunnan Observatories, Chinese Academy of Sciences, 650216 Kunming, Yunnan, China.
²⁶ China Center of Advanced Science and Technology, Beijing 100190, China.
²⁷ College of Physics, Sichuan University, 610065 Chengdu, Sichuan, China.
²⁸ School of Physics, Peking University, 100871 Beijing, China.
²⁹ Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, 530004 Nanning, Guangxi, China.
³⁰ Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
³¹ Moscow Institute of Physics and Technology, 141700 Moscow, Russia.
³² Center for Relativistic Astrophysics and High Energy Physics, School of Physics and Materials Science and Institute of Space Science and Technology, Nanchang University, 330031 Nanchang, Jiangxi, China.
³³ National Space Science Center, Chinese Academy of Sciences, 100190 Beijing, China.
³⁴ School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China.

PMID: 38613275
DOI: 10.1103/PhysRevLett.132.131002

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

Zhen Cao et al. Phys Rev Lett. 2024.

. 2024 Mar 29;132(13):131002.

doi: 10.1103/PhysRevLett.132.131002.

Authors

Affiliations

¹ Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.
² University of Chinese Academy of Sciences, 100049 Beijing, China.
³ Tianfu Cosmic Ray Research Center, 610000 Chengdu, Sichuan, China.
⁴ Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, 2 Dublin, Ireland.
⁵ Max-Planck-Institut for Nuclear Physics, P.O. Box 103980, 69029 Heidelberg, Germany.
⁶ School of Physical Science and Technology and School of Information Science and Technology, Southwest Jiaotong University, 610031 Chengdu, Sichuan, China.
⁷ School of Astronomy and Space Science, Nanjing University, 210023 Nanjing, Jiangsu, China.
⁸ Center for Astrophysics, Guangzhou University, 510006 Guangzhou, Guangdong, China.
⁹ Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong University, 200240 Shanghai, China.
¹⁰ Institute for Nuclear Research of Russian Academy of Sciences, 117312 Moscow, Russia.
¹¹ Hebei Normal University, 050024 Shijiazhuang, Hebei, China.
¹² University of Science and Technology of China, 230026 Hefei, Anhui, China.
¹³ State Key Laboratory of Particle Detection and Electronics, China.
¹⁴ Key Laboratory of Dark Matter and Space Astronomy and Key Laboratory of Radio Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, 210023 Nanjing, Jiangsu, China.
¹⁵ Research Center for Astronomical Computing, Zhejiang Laboratory, 311121 Hangzhou, Zhejiang, China.
¹⁶ Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 200030 Shanghai, China.
¹⁷ School of Physics and Astronomy, Yunnan University, 650091 Kunming, Yunnan, China.
¹⁸ Key Laboratory of Cosmic Rays (Tibet University), Ministry of Education, 850000 Lhasa, Tibet, China.
¹⁹ National Astronomical Observatories, Chinese Academy of Sciences, 100101 Beijing, China.
²⁰ School of Physics and Astronomy (Zhuhai) and School of Physics (Guangzhou) and Sino-French Institute of Nuclear Engineering and Technology (Zhuhai), Sun Yat-sen University, 519000 Zhuhai and 510275 Guangzhou, Guangdong, China.
²¹ Institute of Frontier and Interdisciplinary Science, Shandong University, 266237 Qingdao, Shandong, China.
²² APC, Université Paris Cité, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, 119 75205 Paris, France.
²³ Department of Engineering Physics, Tsinghua University, 100084 Beijing, China.
²⁴ School of Physics and Microelectronics, Zhengzhou University, 450001 Zhengzhou, Henan, China.
²⁵ Yunnan Observatories, Chinese Academy of Sciences, 650216 Kunming, Yunnan, China.
²⁶ China Center of Advanced Science and Technology, Beijing 100190, China.
²⁷ College of Physics, Sichuan University, 610065 Chengdu, Sichuan, China.
²⁸ School of Physics, Peking University, 100871 Beijing, China.
²⁹ Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, 530004 Nanning, Guangxi, China.
³⁰ Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
³¹ Moscow Institute of Physics and Technology, 141700 Moscow, Russia.
³² Center for Relativistic Astrophysics and High Energy Physics, School of Physics and Materials Science and Institute of Space Science and Technology, Nanchang University, 330031 Nanchang, Jiangxi, China.
³³ National Space Science Center, Chinese Academy of Sciences, 100190 Beijing, China.
³⁴ School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China.

PMID: 38613275
DOI: 10.1103/PhysRevLett.132.131002

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.

PubMed Disclaimer

LinkOut - more resources

Full Text Sources
- American Physical Society

Save citation to file

Email citation

Add to Collections

Add to My Bibliography

Your saved search

Create a file for external citation management software

Your RSS Feed

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

Affiliations

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

Authors

Affiliations

Abstract

LinkOut - more resources

Full Text Sources