Jost function description of near threshold resonances for coupled-channel scattering

Resonances in Coupled-Channel Scattering

Excited hadrons are seen as resonances in the scattering of lighter stable hadrons like π , K and η . Many decay into multiple final states necessitating coupled-channel analyses. Recently it has become possible to obtain coupled-channel scattering amplitudes from lattice QCD. Using large diverse bases of operators it is possible to obtain reliable finite volume spectra at energies where multip...

Structure of near-threshold s-wave resonances.

We study the structure of two-body s-wave bound states as well as resonances in the threshold energy region. We focus on the single-channel scattering where the scattering length and the effective range are given by real numbers. It is shown that, in the energy region where the effective range expansion is valid, the properties of resonances are constrained only by the position of the pole. We ...

Coupled-channel evaluations of cross sections for scattering involving particle-unstable resonances.

How does the scattering cross section change when the colliding bound-state fragments are allowed particle-emitting resonances? This question is explored in the framework of a multichannel algebraic scattering method of determining nucleon-nucleus cross sections at low energies. Two cases are examined, the first being a gedanken investigation in which n + 12C scattering is studied with the targ...

Near-threshold behavior of positronium-antiproton scattering

Optical scattering resonances of single and coupled dimer plasmonic nanoantennas.

The optical resonances of individual plasmonic dimer antennas are investigated using confocal darkfield spectroscopy. Experiments on an array of antennas with varying arm lengths and interparticle gap sizes show large spectral shifts of the plasmon modes due to a combination of geometrical resonances and plasmon hybridization. The resonances of the coupled-dimer antennas are considerably broade...