1. Max Planck Institute for Nuclear Physics 1 , Saupfercheckweg 1, 69117 Heidelberg, Germany
2. Heidelberg Graduate School for Physics, Ruprecht Karl University 2 , Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
3. Physikalisch-Technische Bundesanstalt 3 , Bundesallee 100, 38116 Braunschweig, Germany
4. School of Physics and Astronomy, University of Birmingham 4 , Edgbaston, Birmingham B15 2TT, United Kingdom
5. Department of Physics, Humboldt University of Berlin 5 , Newtonstraße 15, 12489 Berlin, Germany
6. Deutsches Elektronen-Synchrotron DESY 6 , Platanenallee 6, 15738 Zeuthen, Germany
7. Institute of Quantum Optics, Leibniz University 7 , Welfengarten 1, 30167 Hannover, Germany