Δ(1232)-Resonance in the Hydrogen Spectrum

Hagelstein, F. (2018). Δ(1232)-Resonance in the Hydrogen Spectrum. Few-Body Systems, 59(5) Springer 10.1007/s00601-018-1403-x

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The electromagnetic excitation of the Δ(1232)-resonance plays an appreciable role in the Lamb shift and hyperfine structure of muonic and electronic hydrogen. Its effect appears at the subleading order O(α5), together with other proton-polarizability contributions from forward two-photon exchange. We use the large-Nc relations for the nucleon-to-delta transition form factors to compute the effect of the Δ(1232) in the hydrogen spectrum. We pay particular attention to a subtile difference between predictions based on a direct calculation of the two-photon exchange (or Compton scattering amplitudes) (Faustov et al. in Phys At Nucl 62:2099, 1999) and predictions based on the Δ(1232)-production photoabsorption cross sections (Buchmann in Can J Phys 87:773–783, 2009). The mismatch is explained by studying the dispersion relations for tree-level Compton scattering off the proton in more details.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Institute of Theoretical Physics

UniBE Contributor:

Hagelstein, Franziska Elfriede

Subjects:

500 Science > 530 Physics

ISSN:

0177-7963

Publisher:

Springer

Language:

English

Submitter:

Esther Fiechter

Date Deposited:

30 Aug 2018 14:50

Last Modified:

02 Sep 2018 02:29

Publisher DOI:

10.1007/s00601-018-1403-x

ArXiv ID:

1801.09790

BORIS DOI:

10.7892/boris.119659

URI:

https://boris.unibe.ch/id/eprint/119659

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