Forward doubly-virtual Compton scattering off the nucleon in chiral perturbation theory: The subtraction function and moments of unpolarized structure functions
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BORIS DOI
Date of Publication
July 7, 2020
Publication Type
Article
Division/Institute
Contributor
Alarcón, Jose Manuel | |
Lensky, Vadim | |
Pascalutsa, Vladimir |
Subject(s)
Series
Physical review. D - particles, fields, gravitation, and cosmology
ISSN or ISBN (if monograph)
1550-7998
Publisher
American Physical Society
Language
English
Publisher DOI
Description
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.
File(s)
File | File Type | Format | Size | License | Publisher/Copright statement | Content | |
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PhysRevD102(2020.pdf | Adobe PDF | 823.67 KB | Attribution (CC BY 4.0) | published |