Journal Article

FZJ-2016-01045

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png High-Precision Determination of the Pion-Nucleon σ Term from Roy-Steiner Equations

Hoferichter, M. ; Ruiz de Elvira, J. ; Kubis, B. ; Meißner, U.-G.FZJ*

2015
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/9767  doi:10.1103/PhysRevLett.115.092301

Abstract: We present a determination of the pion-nucleon ($\pi N$) $\sigma$-term $\sigma_{\pi N}$ based on the Cheng-Dashen low-energy theorem (LET), taking advantage of the recent high-precision data from pionic atoms to pin down the $\pi N$ scattering lengths as well as of constraints from analyticity, unitarity, and crossing symmetry in the form of Roy-Steiner equations to perform the extrapolation to the Cheng-Dashen point in a reliable manner. With isospin-violating corrections included both in the scattering lengths and the LET, we obtain $\sigma_{\pi N}=(59.1\pm 1.9\pm 3.0)$ MeV $=(59.1\pm 3.5)$ MeV, where the first error refers to uncertainties in the $\pi N$ amplitude and the second to the LET. Consequences for the scalar nucleon couplings relevant for the direct detection of dark matter are discussed.

Note: 6 pages, 1 figure; title changed by journal, version to be published in PRL

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Contributing Institute(s):

1. Theorie der Starken Wechselwirkung (IAS-4)
2. Theorie der starken Wechselwirkung (IKP-3)

Research Program(s):

1. 511 - Computational Science and Mathematical Methods (POF3-511) (POF3-511)
2. DFG project 196253076 - TRR 110: Symmetrien und Strukturbildung in der Quantenchromodynamik (196253076) (196253076)

Appears in the scientific report 2015

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Database coverage:
; ; Current Contents - Physical, Chemical and Earth Sciences ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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