Interplay between the 0+_2 resonance and the nonresonant continuum of the drip-line two-neutron halo nucleus 22C

TL;DR

This study investigates how the 0+_2 resonance and nonresonant continuum influence the breakup cross section of the two-neutron halo nucleus 22C, revealing a Fano effect caused by their interplay.

Contribution

It introduces a detailed analysis of the 0+_2 resonance's coupling with the nonresonant continuum in 22C using advanced computational methods, highlighting the Fano effect in breakup reactions.

Findings

The 2+_1 resonance produces a narrow peak in the breakup cross section.

The 0+_2 resonance exhibits a peculiar shape due to the Fano effect.

The shape of the 0+_2 resonant cross section varies with scattering angle.

Abstract

The breakup cross section (BUX) of 22C by 12C at 250 MeV/nucleon is evaluated by the continuum-discretized coupled-channels method incorporating the cluster-orbital shell model (COSM) wave functions. Contributions of the low-lying 0+_2 and 2+_1 resonances predicted by COSM to the BUX are investigated. The 2+_1 resonance gives a narrow peak in the BUX, as in usual resonant reactions, whereas the 0+_2 resonant cross section has a peculiar shape due to the coupling to the nonresonant continuum, i.e., the Fano effect. By changing the scattering angle of 22C after the breakup, a variety of shapes of the 0+_2 resonant cross sections is obtained. Mechanism of the appearance of the sizable Fano effect in the breakup of 22C is discussed.