Affiliation: | a Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China;b School of Science, Huzhou Teachers College, Huzhou 313000, PR China;c Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, PR China;d Graduate University of Chinese Academy of Sciences, Beijing 100049, PR China;e Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA |