Purple Mountain Observatory;
Chinese Academy of Sciences;
Nanjing 210008;
China;
Graduate University of Chinese Academy of Sciences;
Beijing 100049;
China;
Joint Center for Particle Nuclear Physics and Cosmology (J-CPNPC);
Nanjing 210093;
China;
Department of Astronomy & Astrophysics;
Pennsylvania State University;
University Park;
PA 16802;
USA;
Department of Physics;
Huazhong University of Science and Technology;
Wuhan 430074;
China;