1. Department of Astronomy and Astrophysics, University of Toronto , 50 St George Street, Toronto, ON M5S 3H4, Canada
2. Carnegie Observatories , 813 Santa Barbara Street, Pasadena, CA 91101, USA
3. Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University , Stanford, CA 94305, USA
4. SLAC National Accelerator Laboratory , Menlo Park, CA 94025, USA
5. Department of Physics and Astronomy, University of California , Los Angeles, CA 90095, USA
6. Department of Physics, University of California Merced , 5200 North Lake Road Merced, CA 95343, USA