In the first part of this Chapter the present state of knowledge from the observations of cosmic rays between 10$^{13}$ and 10$^{20}$ eV is summarized. This is not intended to be a complete review, but rather a broad overview of the relevant processes involving cosmic rays, including the astrophysical environments in which they take place. This overview mainly concerns experimental results and phenomenological aspects of their interpretation, therefore experiments’ description is not given but references to the vast bibliography are provided in the text. Some attempt is made to address the most popular explanations offered by theoretical models. The second part is devoted to the description of the LHAASO performance and of its capability to provide a response to several open questions, still unanswered, concerning cosmic rays above 10$^{13}$ eV, highlighting which major steps forward in this field could be taken from LHAASO observations.

Italy

Benedetto D’Ettorre Piazzoli

China

Si-Ming Liu

Switzerland

Domenico della Volpe

Zhen Cao

Andrea Chiavassa

Yi-Qing Guo

Russia

Leonid T. Ksenofontov

France

Olivier Martineau-Huynh

Diane Martraire

Ling-Ling Ma

Xin-Hua Ma

Yuri Stenkin

Qiang Yuan

Hou-Dun Zeng

Shou-Shan Zhang

Yi Zhang

Hui Zhu

Chapter 4 Cosmic-Ray Physics  

The Large High Altitude Air Shower Observatory (LHAASO) (Fig. 1) is located at Mt. Haizi (4410 m a.s.l., 600 g/cm$^{2}$, 29° 21’ 27.56” N, 100° 08’ 19.66” E) in Daocheng, Sichuan province, P.R. China. LHAASO consists of 1.3 km$^{2}$ array (KM2A) of electromagnetic particle detectors (ED) and muon detectors (MD), a water Cherenkov detector array (WCDA) with a total active area of 78,000 m$^{2}$, 18 wide field-of-view air Cherenkov telescopes (WFCTA) and a newly proposed electron-neutron detector array (ENDA) covering 10,000 m$^{2}$. Each detector is synchronized with all the other through a clock synchronization network based on the White Rabbit protocol. The observatory includes an IT center which comprises the data acquisition system and trigger system, the data analysis facility. In this Chapter, all the above-mentioned components of LHAASO as well as infrastructure are described.

Yu-Jiang Bi

Ming-Jun Chen

Song-Zhan Chen

Yao-Dong Cheng

Guang-Hua Gong

Min-Hao Gu

Hui-Hai He

Chao Hou

Wen-Hao Huang

Xing-Tao Huang

Cheng Liu

Oleg Shchegolev

Xiang-Dong Sheng

Chao-Yong Wu

Han-Rong Wu

Sha Wu

Gang Xiao

Zhi-Guo Yao

Xiong Zuo

Chapter 1 LHAASO Instruments and Detector technology  

We consider right-handed neutrino dark matter N1 in local U(1)LÎ¼âLÏ -extended Ma model. With the light U(1)Î¼âÏ gauge boson ( mZâ²â¼O(100)Â MeV ) and small U(1)Î¼âÏ gauge coupling ( gZâ²â¼10â4â10â3 ) which can accommodate the muon (gâ2) anomaly and is still allowed by other experimental constraints, we show that we can get correct relic density of dark matter for wide range of dark matter mass ( M1â¼10â200Â GeV ), although the gauge coupling constant gZâ² is small. This is due to the fact that the annihilation cross section of dark matter pair is enhanced by M14/mZâ²4 in the processes N1N1âZâ²Zâ² or N1N1âZâ²H2 . We also consider the constraints from direct detection, collider searches.

South Korea

Seungwon Baek

Dark matter and muon ( g − 2) in local U(1)Lμ−Lτ -extended Ma model