Institute of High Energy Physics CAS Beijing 100049 China;
Graduate University of Chinese Academy of Sciences Beijing 100049 China;
University of Colorado Boulder Colorado 80309 USA;
Nanjing University Nanjing 210093 China;
Tsinghua University Beijing 100084 China;
Zhengzhou University Zhengzhou 450001 China;
Shandong University Jinan 250100 China;
Peking University Beijing 100871 China;
Liaoning University Shenyang 110036 China;
Guangxi Normal University Guilin 541004 China;
Department of Modern Physics University of Science and Technology of China Hefei 230026 China;
CCAST(World Laboratory) Beijing 100080 China;
BESⅢ detector; track reconstruction; track segment finder; conformal transformation; secondary vertex;