Stuttgart 2012 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 16: Präzisionsmessungen und Metrologie 3
Q 16.1: Talk
Monday, March 12, 2012, 16:30–16:45, V7.03
Precision spectroscopy of the 2S1/2−4P1/2 transition in atomic hydrogen — •Axel Beyer1, Arthur Matveev1, Christian G. Pathey1, Janis Alnis1, Randolf Pohl1, Nikolai Kolachevsky1, Thomas Udem1, and Theodor W. Hänsch1,2 — 1Max-Planck-Institut für Quantenoptik, 85748 Garching — 2Ludwig-Maximilians-Universität, 80799 München
The comparison between measured and calculated transition frequencies in atomic hydrogen can provide stringent tests of bound state QED. For the last decade, this comparison has been limited by the proton charge radius determined by electron-proton scattering. Recently, laser spectroscopy of muonic hydrogen provided a value, which is ten times more accurate than any previous measurement (Pohl et al., Nature 466(7303), 2010). But this value differs from the CODATA 2010 value, obtained by a global adjustment of fundamental constants using data from electron-proton scattering and hydrogen experiments for the proton charge radius, by seven standard deviations. The muonic hydrogen result led to a comprehensive search for the cause of this discrepancy, but no convincing argument could be found so far. Because the current CODATA value is mainly based on observations in atomic hydrogen, transition frequency measurements with improved accuracy can help to solve this puzzle or at least to rule out hydrogen experiments as a possible source for the discrepancy. Here we report on the setup which has been developed for the measurement of the one-photon 2S1/2-4P1/2 transition frequency in atomic hydrogen along with the results and conclusions of our first measurement runs.