Alarcón, Jose Manuel; Hagelstein, Franziska; Lensky, Vadim; Pascalutsa, Vladimir (2020). Forward doubly-virtual Compton scattering off the nucleon in chiral perturbation theory: The subtraction function and moments of unpolarized structure functions. Physical review. D - particles, fields, gravitation, and cosmology, 102(1), 014006. American Physical Society 10.1103/PhysRevD.102.014006
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The forward doubly-virtual Compton scattering (VVCS) off the nucleon contains a wealth of information on nucleon structure, relevant to the calculation of the two-photon-exchange effects in atomic spectroscopy and electron scattering. We report on a complete next-to-leading-order (NLO) calculation of low-energy VVCS in chiral perturbation theory (χPT). Here we focus on the unpolarized VVCS amplitudes T1ðν;Q2Þ and T2ðν;Q2Þ, and the corresponding structure functions F1ðx;Q2Þ and F2ðx;Q2Þ. Our results are confronted, where possible, with “data-driven” dispersive evaluations of low- energy structure quantities, such as nucleon polarizabilities. We find significant disagreements with dispersive evaluations at very low momentum-transfer Q; for example, in the slope of polarizabilities at zero momentum transfer. By expanding the results in powers of the inverse nucleon mass, we reproduce the known “heavy-baryon” expressions. This serves as a check of our calculation, as well as demonstrates the differences between the manifestly Lorentz-invariant (BχPT) and heavy-baryon (HBχPT) frameworks.
Item Type: |
Journal Article (Original Article) |
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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: |
1550-7998 |
Publisher: |
American Physical Society |
Language: |
English |
Submitter: |
Esther Fiechter |
Date Deposited: |
05 Aug 2020 15:49 |
Last Modified: |
05 Dec 2022 15:39 |
Publisher DOI: |
10.1103/PhysRevD.102.014006 |
ArXiv ID: |
2005.09518 |
BORIS DOI: |
10.7892/boris.145597 |
URI: |
https://boris.unibe.ch/id/eprint/145597 |
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