Evidence for a secondary bow in Newton's zero-order nuclear rainbow

TL;DR

This paper provides experimental evidence for a secondary nuclear rainbow in quantum nuclear scattering, generated dynamically without internal reflection, expanding understanding of nuclear rainbow phenomena.

Contribution

It demonstrates the existence of a secondary nuclear rainbow caused by dynamic coupling to an excited state, not internal reflection, using coupled channel calculations.

Findings

Evidence for a secondary nuclear rainbow in $^{16}$O+$^{12}$C scattering.

The secondary rainbow is generated dynamically by coupling to an excited state.

The study extends the understanding of nuclear rainbow phenomena.

Abstract

Rainbows are generally considered to be caused by static refraction and reflection. A primary and a secondary rainbow appear due to refraction and internal reflection in a raindrop as explained by Newton. The quantum nuclear rainbow, which is generated by refraction in the nucleus droplet, only has a "primary" rainbow. Here we show for the first time evidence for the existence of a secondary nuclear rainbow generated dynamically by coupling to an excited state without internal reflection. This has been demonstrated for experimental $^{16}$O+$^{12}$C scattering using the coupled channel method with an extended double folding potential derived from microscopic realistic wave functions for $^{12}$C and $^{16}$O.