Reaction mechanism in odd-even staggering of reaction cross sections

TL;DR

This paper investigates the relationship between odd-even staggering of reaction cross sections and projectile radii, analyzing how breakup and medium effects influence this relationship using microscopic scattering models.

Contribution

It introduces a detailed analysis of the connection between staggering parameters for radii and cross sections, accounting for breakup and medium effects with a microscopic coupled-channels approach.

Findings

Projectile-breakup and medium effects nearly cancel each other.

Non-black-sphere scattering effects diminish at lower energies.

Lower incident energies are better for probing projectile radii from cross sections.

Abstract

It was recently suggested that the odd-even staggering of reaction cross sections is an evidence of the pair- ing anti-halo effect on projectile radii. We define the dimensionless staggering parameters, {\Gamma}rds and {\Gamma}R, for projectile radii and reaction cross sections, respectively, and analyze the relation between {\Gamma}rds and {\Gamma}R for the scattering of 14,15,16C from a 12C target at 83 MeV/A by taking account of projectile-breakup and nuclear- medium effects newly with the microscopic version of the continuum discretized coupled-channels method. The value of {\Gamma}R is deviated from that of {\Gamma}rds by the projectile-breakup effect, the nuclear-medium effect and an effect due to the fact that the scattering are not the black-sphere scattering (BSS) exactly. The projectile-breakup and nuclear medium effects are nearly canceled for {\Gamma}R. The remaining non-BSS effect becomes small as an incident energy decreases, indicating that nucleus-nucleus scattering at lower incident energies are a good probe of evaluating {\Gamma}rds from measured reaction cross sections.