Superhalo of ${}^{22}\mathrm{C}$ reexamined

An unusually large value of the ${}^{22}\mathrm{C}$ matter radius, extracted by Tanaka et al. [Phys. Rev. Lett. 104, 062701 (2010)] from measured reaction cross sections, attracted great attention of scientific community. Since that time, several experimental works related to the ${}^{22}\mathrm{C}$ nucleus have appeared in the literature. Some of the experimental data, measured with high accuracy, allow us to fix ${}^{22}\mathrm{C}$ structure more reliably. Two limiting models reproducing ${}^{22}\mathrm{C}$ nuclear structure within the three-body cluster approach, that allow us to describe all existing experimental data, are presented. The ${}^{22}\mathrm{C}$ ground state, continuum structure, and geometry are obtained. With fixed ${}^{22}\mathrm{C}$ wave function, the prediction for the soft dipole mode in ${}^{22}\mathrm{C}$, which is studied in the process of Coulomb fragmentation, is performed.

Figure 1

Phases in ${}^{20}\mathrm{C}$-n $s$-wave scattering. Upper solid line, phases obtained in original deep Horiuchi-Suzuki potential; upper dotted line, in-phase equivalent potential with repulsive core in $s$-wave; lower solid line, in-P1 potential, providing unbound ${}^{21}\mathrm{C}$; lower dashed line, in-P2 potential, based on the experiment [17] by Mosby et al.

Figure 2

Phases in ${}^{20}\mathrm{C}$-n $d_{3/2}$-wave scattering. Solid line, phases obtained in modified Horiuchi-Suzuki potential P1; dotted line, in-P2 potential, based on the experiment [17] by Mosby et al.

Figure 3

Main components ($K,l_x,l_y$) of the ${}^{22}\mathrm{C}$ wave function for P1 potential.

Figure 4

Main components ($K,l_x,l_y$) of the ${}^{22}\mathrm{C}$ wave function for P2 potential.

Figure 5

The ${}^{22}\mathrm{C}$ correlation density for P1 potential.

Figure 6

Longitudinal momentum distribution of ${}^{20}\mathrm{C}$ core after ${}^{22}\mathrm{C}$ fragmentation on ${}^{12}\mathrm{C}$ target for P1 potential (solid line) and for P2 potential (dashed line). Points are experimental data from Ref. [16].

Figure 7

Longitudinal momentum distribution of ${}^{20}\mathrm{C}$ core after ${}^{22}\mathrm{C}$ fragmentation on ${}^{12}\mathrm{C}$ target for P1 potential (a) and for P2 potential (b). Solid lines, total LMD; dashed line, K = 0 contribution; dash-dotted line, $K>0$ contribution. Both LMD are normalized to unity.

Figure 8

Calculated ${}^{22}\mathrm{C}$ dipole strength functions for P1 potential (solid line) and for P2 potential (dashed line).

Figure 9

Correlations for ${}^{22}\mathrm{C}$ Coulomb dissociation in T system for P2 potential at $E_f$ = 0.5 MeV (a) and $E_f$ = 4.0 MeV (b).

Figure 10

Calculated ${}^{22}\mathrm{C}$ Coulomb dissociation cross sections as a function of relative three body energy in continuum for P1 potential (solid line) and for P2 potential (dashed line).