Dr. Tobias Nebel, a young research scientist at the Max Planck Institute of Quantum Optics, has been awarded the 2010 Otto Hahn Medal for the first measurement of the Lamb shift in muonic hydrogen and the resulting redefinition of the radius of the proton. Since 1978, the Max Planck Society has annually honored up to 40 young scientists for their research with the hope of encouraging other talented people to pursue a career in fundamental research.

The measurements on the muonic hydrogen atoms took place in collaboration with several research institutes at the Paul Scherrer Institute in Villigen, Switzerland. In these exotic atoms, the outer electron is replaced by the 200-times-heavier muon, which gets much closer to the nucleus and literally “feels” its extension. The spectroscopic determination of the Lamb shift of the energy levels in muonic hydrogen in 2010 yielded a value for the proton radius which was significantly smaller than deduced from previous measurements — a fact that still puzzles the scientific community.

Nebel, born in 1976, studied physics at the University of Augsburg, at the University of British Columbia in Vancouver, Canada, and at the Ludwig-Maximilians University in Munich, where he received his doctoral degree at the chair of professor Theodor W. Hänsch in 2010. His thesis on the Lamb shift in muonic hydrogen was carried out at the Max Planck Institute of Quantum Optics in the Laser Spectroscopy Division.

Nebel has already received the Government of Canada Award for graduate studies in Canada. He will be presented with the Otto Hahn Medal on the occasion of the main assembly of the Max Planck Society in Berlin on June 8, 2011.

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