作者机构:[1]Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China, [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China, [3]Center for High Energy Physics, Tsinghua University, Beijing 100084, China, [4]Theoretical Physics Institute, Chongqing University, Chongqing 400044, China
相关基金:Supported by NSFC (10435070, 10721140381, 10099630), China Ministry of Science and Technology (2007CB16101), CAS (KJCX2-N17, 1730911111) and China Postdoctoral Science Foundation (20090450577) We are grateful to Profs. Y.-P. Kuang and H.-J He for their helpful discussions.