C. Bernerd⁷, A. Borschevsky¹⁰, A. A. Breier^11,12, K. Chrysalidis⁷, T. E. Cocolios², R. P. de Groote², C. M. Fajardo-Zambrano², K. T. Flanagan^6,13, S. Franchoo¹⁴, R. F. Garcia Ruiz^4,5, D. Hanstorp¹⁵, R. Heinke⁷, P. Imgram², Á. Koszorús^1,2, A. A. Kyuberis¹⁰, J. Lim³, Y. C. Liu⁹, K. M. Lynch⁶, A. McGlone⁶, W. C. Mei⁹, G. Neyens^2,†, L. Nies¹, A. V. Oleynichenko¹⁶, A. Raggio¹⁷, S. Rothe⁷, L. V. Skripnikov¹⁶, E. Smets², B. van den Borne², J. Warbinek^18,19, J. Wessolek^6,7, and X. F. Yang⁹

• ¹Experimental Physics Department, CERN, CH-1211 Geneva 23, Switzerland
• ²KU Leuven, Instituut voor Kern- en Stralingsfysica, B-3001 Leuven, Belgium
• ³Centre for Cold Matter, Imperial College London, London SW7 2AZ, United Kingdom
• ⁴Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
• ⁵Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
• ⁶Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, United Kingdom
• ⁷Systems Department, CERN, CH-1211 Geneva 23, Switzerland
• ⁸Department of Chemistry, Johannes Gutenberg-Universität Mainz, D-55128 Mainz, Germany
• ⁹School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100971, China
• ¹⁰Van Swinderen Institute of Particle Physics and Gravity, University of Groningen, NL-9747 CP Groningen, Netherlands
• ¹¹Institut für Optik und Atomare Physik, Technische Universität Berlin, D-10623 Berlin, Germany
• ¹²Laboratory for Astrophysics, Institute of Physics, University of Kassel, D-34132 Kassel, Germany
• ¹³Photon Science Institute, The University of Manchester, Manchester M13 9PY, United Kingdom
• ¹⁴Laboratoire Irène Joliot-Curie, CNRS/IN2P3 and University Paris-Saclay, 91405 Orsay, France
• ¹⁵Department of Physics, University of Gothenburg, SE-41296 Gothenburg, Sweden
• ¹⁶Affiliated with an institute covered by a cooperation agreement with CERN
• ¹⁷Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
• ¹⁸GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
• ¹⁹Department of Chemistry - TRIGA Site, Johannes Gutenberg-Universität Mainz, D-55128 Mainz, Germany

• ^*Contact author: m.athkak@cern.ch
• ^†Contact author: gerda.neyens@kuleuven.be