Precision spectroscopy of 2S–nP transitions in atomic hydrogen for a new determination of the Rydberg constant and the proton charge radius. (7th October 2015)

• Record Type: Journal Article
• Authors: Beyer, Axel; Maisenbacher, Lothar; Khabarova, Ksenia; Matveev, Arthur; Pohl, Randolf; Udem, Thomas; Hänsch, Theodor W; Kolachevsky, Nikolai
• Is Part Of: Physica scripta. Volume T165(2015:Oct.)
• Publication Date: 2015-10-07
• Subjects: precision spectroscopy -- atomic hydrogen -- Rydberg constant -- proton charge radius -- proton size puzzle -- quantum interference -- Doppler shift; Physics -- Periodicals; 530.05
• DOI: 10.1088/0031-8949/2015/T165/014030
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: Precision measurements of transition frequencies in atomic hydrogen provide important input for a number of fundamental applications, such as stringent tests of QED and the extraction of fundamental constants. Here we report on precision spectroscopy of the 2S–4P transition in atomic hydrogen with a reproducibility of a few parts in 10 12 . Utilizing a cryogenic beam of hydrogen atoms in the metastable 2S state reduces leading order systematic effects of previous experiments of this kind. A number of different systematic effects, especially line shape modifications due to quantum interference in spontaneous emission, are currently under investigation. Once fully characterized, our measurement procedure can be applied to higher lying 2S– n P transitions ( ) and we hope to contribute to an improved determination of the Rydberg constant and the proton root mean square charge radius by this series of experiments. Ultimately, this improved determination will give deeper insight into 'the proton size puzzle' from the electronic hydrogen side.