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

In this paper we show how rotational bands of resonances can be described byusing trajectories of poles of the scattering amplitude in the complex angularmomentum plane: each band of resonances is represented by the evolution of asingle pole lying in the first quadrant of the plane. The main result of thepaper consists in showing that also the antiresonances (or echoes) can bedescribed by trajectories of the scattering amplitude poles, instead of usingthe hard-sphere potential scattering as prescribed by the classicalBreit-Wigner theory. The antiresonance poles lie in the fourth quadrant of thecomplex angular momentum plane, and are associated with non-local potentialswhich take into account the exchange forces; it derives a clear-cut separationbetween resonance and antiresonance poles. The evolution of these latter polesdescribes the passage from quantum to semi-classical physics. The theory istested on the rotational band produced by $\alpha$-$\alpha$ elastic scatteringand on the hadronic rotational bands in $\pi^+$-p elastic scattering.Comment: 26 pages, 4 figures, to be published in Phys. Rev.

Unified scheme for describing time delay and time advance in the interpolation of rotational bands of resonances