Eta-nuclear interaction: optical vs. coupled channels

TL;DR

This paper compares optical and coupled channels models for eta-nuclear interactions, showing that explicit coupling reduces absorption and may allow for narrow eta-nuclear states, impacting experimental detection prospects.

Contribution

It demonstrates that coupled channels models predict smaller imaginary parts than optical models, suggesting potential for narrower eta-nuclear states.

Findings

Coupled channels yield smaller imaginary parts than optical models.

Reduced absorption increases the likelihood of narrow eta-nuclear states.

Implications for experimental detection of eta-nuclei.

Abstract

The existence of etamesic nuclei has been speculated for a long time without firm experimental evidence. Much of the effort has taken place in final state interactions on production. One crucial factor in seeing a quasibound state is its width, which should be related to the imaginary part of the scattering length. Comparing two models for eta-N scattering giving the same elementary scattering length, a simple optical potential and an explicit coupling to the pionic channel, it is seen that the latter yields a much smaller imaginary part for eta-nucleus scattering. This decrease of absorption may also mean a possibility for narrow eta-nuclear states.