1. Clarendon Laboratory, Department of Physics, Oxford University, Parks Road, Oxford OX1 3PU, U.K., ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX11 0QX, U.K., TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada, Department of Physics, University of Alberta, Edmonton, Alberta T6G 2G7, Canada, Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada, Department of Chemistry, University of British Columbia,...