English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We calculate the pion-nucleon scattering lengths $a_{0}^{(\pm)}$ and the massparameter $m_{0}$, which describes the nucleon mass in the chiral limit, attree-level in the framework of a globally symmetric linear sigma model withparity-doubled nucleons. When recent lattice results [Takahashi] are used, weobtain $m_{0}\simeq300-600$ MeV. While $a_{0}^{(-)}$ is in fair agreement withexperimental data, $a_{0}^{(+)}$ is too small because of the employed largescalar meson mass. This indicates the need to account for additional scalardegrees of freedom.

The chiral partner of the nucleon in the mirror assignment with global symmetry