Erlangen 2018 – scientific programme

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A: Fachverband Atomphysik

A 39: Precision Spectroscopy VI - neutrals and ions (joint session A/Q)

A 39.1: Invited Talk

Thursday, March 8, 2018, 14:00–14:30, K 1.016

News from the "Proton Radius Puzzle" — •Randolf Pohl — Johannes Gutenberg Universität Mainz

The Proton Radius Puzzle [1] is the 5 sigma discrepancy between the charge radius measured in muonic hydrogen [2] on the one hand, and in regular hydrogen and elastic electron scattering on the other [3]. I will report on several new measurements in muonic and electronic atoms, which have recently started to shed light on the discrepancy. These include measurements in muonic deuterium [4], helium-3 and helium-4, as well as a new measurement in regular hydrogen [5]. In the outlook, I will present ongoing and planned measurements of the CREMA Collaboration targeting the (magnetic) Zemach radius of the proton [6], and the charge radii of other light nuclei.
[1] J.C. Bernauer, R. Pohl, Spektrum der Wiss., April 2014

[2] A. Antognini et al., (CREMA Collab.), Science 339, 417 (2013)

[3] P. Mohr et al. (CODATA-2014), Rev. Mod. Phys. 88, 035009 (2016)

[4] R. Pohl et al., (CREMA Collab.), Science 353, 669 (2016)

[5] A. Beyer et al., Science 358, 79 (2017)

[6] R. Pohl et al., J. Phys. Soc. Japan Conf. Proc. 18, 011021 (2017)