Extracting $σ_{πN}$ from pionic atoms
Year: 2020
Type: preprint
Abstract: We discuss a recent extraction of the $πN$ $σ$ term $σ_{πN}$ from a large-scale fit of pionic-atom strong-interaction data across the periodic table. The value thus derived, $σ_{πN}^{\rm FG}=57\pm 7$ MeV, is directly connected via the Gell-Mann--Oakes--Renner expression to the medium-renormalized $πN$ isovector scattering amplitude near threshold. It compares well with the value derived recently by the Bern-Bonn-Jülich group, $σ_{πN}^{\rm RS}=58\pm 5$ MeV, using the Roy-Steiner equations to control the extrapolation of the vanishingly small near threshold $πN$ isoscalar scattering amplitude to zero pion mass.
Source: arXiv (Cornell University)
Authors: Friedman, Eliahu, Gal, Avraham
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W6948323799
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