[1] Univ Bio Bio, Dept Fis, Grp Cosmol & Particulas Elementales, Casilla 5-C, Concepcion 4051381, Chile
[2] Univ Diego Portales, Fac Ingn & Ciencias, Ave Ejercito Libertador 441,Casilla 298-V, Santiago, Chile
[3] Pontificia Univ Catolica Valparaiso, Inst Fis, Casilla 4950, Valparaiso, Chile
[4] Univ La Serena, Fac Ciencias, Dept Fis, Ave Cisternas 1200, La Serena, Chile
[5] Shanghai Jiao Tong Univ, Sch Aeronaut & Astronaut, Shanghai 200240, Peoples R China
[6] Yangzhou Univ, Coll Phys Sci & Technol, Ctr Gravitat & Cosmol, Yangzhou 225009, Jiangsu, Peoples R China