1. École Polytechnique Fédérale de Lausanne, Laboratory for Quantum Magnetism, 1015 Lausanne, Switzerland
2. Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, 5232 Villigen, Switzerland
3. Paul Scherrer Institute, Laboratory for Scientific Developments and Novel Materials, 5232 Villigen, Switzerland
4. Wigner Research Centre for Physics, Neutron Spectroscopy Department, 1525 Budapest, Hungary
5. Department of Quantum Matter Physics, University of Geneva, 1211 Geneva, Switzerland
6. University of Copenhagen, Niels Bohr Institute, 2100 Copenhagen, Denmark