Renormalization of the isovector $\pi N$ amplitude in pionic atoms

Abstract

The extraction of the isovector s-wave pi N amplitude from pionic atoms is studied with special emphasis on uncertainties and their dependence on the assumptions made regarding the neutron density distributions in nuclei and on the size of the data base used . Only `global' analyses of pionic-atom data reveal a discrepancy between the extracted isovector s-wave pi N amplitude b_1=-0.108\pm0.007 m_π^{-1} and its free pi N counterpart b_1^{free}=-0.0885^{+0.0010}_{-0.0021} m_π^{-1}, where the uncertainty in the neutron densities is included in the error analysis. The role of `deeply bound' pionic atom states is discussed and the reason for failure of these states to provide new information is explained.

arXiv comment17 pages, 4 figures, slightly extended, accepted by NPA

References in corpus (8)

• Chiral Dynamics of Deeply Bound Pionic Atoms
• Determination of the pion-nucleon coupling constant and scattering lengths
• Neutron Densities from a Global Analysis of Medium Energy Proton Nucleus Elastic Scattering
• Systematic calculation of s-wave pion and kaon self-energies in asymmetric nuclear matter
• Evidence for partial chiral symmetry restoration from pionic atoms
• Ground state properties of the $\beta$ stable nuclei in various mean field theories
• Density dependence of the s-wave repulsion in pionic atoms
• On the determination of the pion effective mass in nuclei from pionic atoms

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• Nuclear bound state of eta'(958) and partial restoration of chiral symmetry in the eta' mass
• Antiproton-nucleus potentials from global fits to antiprotonic X-rays and radiochemical data
• The pion-nucleon $\sigma$ term from pionic atoms
• The in-medium isovector pi N amplitude from low energy pion scattering
• Chiral symmetry restoration at high matter density observed in pionic atoms
• Elastic scattering of low energy pions by nuclei and the in-medium isovector pi N amplitude
• Possibility of s-wave pion condensates in neutron stars revisited
• Reaction cross section described by a black sphere approximation of nuclei
• Testing Chiral Dynamics in Pionic Atoms
• Testing in-medium $\pi N$ dynamics on pionic atoms
• Antiprotonic Potentials from Global Fits to the PS209 Data
• Overview of pion-nucleus interaction at low energies