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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present a dispersive representation of the $\gamma N\rightarrow \pi N$partial-wave amplitude based on unitarity and analyticity. In thisrepresentation, the right-hand-cut contribution responsible for $\pi N$final-state-interaction effect are taken into account via an Omn\'es formalismwith elastic $\pi N$ phase shifts as inputs, while the left-hand-cutcontribution is estimated by invoking chiral perturbation theory. Numericalfits are performed in order to pin down the involved subtraction constants. Itis found that good fit quality can be achieved with only one free parameter andthe experimental data of the multipole amplitude $E_{0}^+$ in the energy regionbelow the $\Delta(1232)$ are well described. Furthermore, we extend the $\gammaN\rightarrow \pi N$ partial-wave amplitude to the second Riemann sheet so as toextract the couplings of the $N^\ast(890)$. The modulus of the residue of themultipole amplitude $E_{0}^+$ ($S_{11pE}$) is $2.41\rm{mfm\cdot GeV^2}$ and thepartial width of $N^*(890)\to\gamma N$ at the pole is about $0.369\ {\rm MeV}$,which is almost the same as the one of $N^*(1535)$, indicating that$N^\ast(890)$ strongly couples to $\pi N$ system.

Dispersive Analysis of Low Energy $\gamma N\to\pi N$ Process and Studies on the $N^*(890)$ Resonance