[1] Univ Parma, Dipartimento SMFI, Parma, Italy
[2] Ist Nazl Fis Nucl, Grp Collegato Parma, Parma, Italy
[3] Stanford Univ, Stanford Inst Theoret Phys, Phys Dept, Stanford, CA 94306 USA
[4] SLAC, Kavli Inst Particle Astrophys & Cosmol, Menlo Pk, CA 94025 USA
[5] Stanford Univ, Menlo Pk, CA 94025 USA
[6] Univ Sci & Technol China, Sch Phys Sci, Dept Astron, Hefei 230026, Anhui, Peoples R China
[7] Univ Sci & Technol China, CAS Key Lab Res Galaxies & Cosmol, Hefei 230026, Anhui, Peoples R China
[8] Univ Sci & Technol China, Sch Astron & Space Sci, Hefei 230026, Anhui, Peoples R China