1. Physics/Astronomy Department, University of Arkansas at Little Rock, Little Rock, AR 72204, USA
2. School of Physics, Peking University, Beijing, 100871, China
3. Physics Department, Pennsylvania State University, University Park, PA 16802, USA
4. Department of Physics, University at Buffalo, Buffalo, NY 14228, USA
5. Physics Department, Ubon Rajathanee University, Warinchamrab, Ubon 34190, Thailand
6. College of Education, University of Arkansas at Little Rock, Little Rock, AR 72204, USA