1. European Organization for Nuclear Research (CERN), Esplanade des Particules 1, 1217 Meyrin, Switzerland
2. Lund University, Lund University Physics Education Research (LUPER) Group, Box 118, 221 00 Lund, Sweden
3. University of Göttingen, Faculty of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
4. Utrecht University, Freudenthal Institute, Princetonplein 5, 3584 CC Utrecht, The Netherlands
5. Technische Universität Dresden, Institute of Nuclear and Particle Physics, 01069 Dresden, Germany
6. University of Vienna, AECC Physics, Porzellangasse 4/2/2, 1090 Vienna, Austria