Exploring the anomaly in the interaction cross section and matter radius of ${}^{23}$O

New measurements of the interaction cross sections of ${}^{22,23}$O at 900$A$ MeV performed at the GSI, Darmstadt are reported that address the unsolved puzzle of the large cross section previously observed for ${}^{23}$O. The matter radii for these oxygen isotopes extracted through a Glauber model analysis are in good agreement with the new predictions of the ab initio coupled-cluster theory reported here. They are consistent with a ${}^{22}\mathrm{O}+\mathrm{neutron}$ description of ${}^{23}$O as well.

Figure 1

The interaction cross section of ${}^A\mathrm{O}+\mathrm{C}$ as a function of the mass number. The circles represent the present data, and the squares are from Ref. [1]. The line shows the $A^{1/3}$ dependence normalized to ${}^{16}$O.

Figure 2

The interaction cross-section data for (a) ${}^{22}\mathrm{O}+\mathrm{C}$ and (b) ${}^{23}\mathrm{O}+\mathrm{C}$ (shaded regions). The filled squares are Glauber model calculations with Fermi density parameters $r_0$ and $a$ shown as a function of $R_{\mathrm{rms}}^m{(}^A\mathrm{O})$. The dotted lines show a guide to the eye for determining the limits of $R_{\mathrm{rms}}^m$ consistent with the data. The solid lines guiding the open squares, are calculations with harmonic oscillator density. (c) The interaction cross-section data for ${}^{23}\mathrm{O}+\mathrm{C}$ (shaded region). The dashed (dotted) line is a ${}^{22}\mathrm{O}+n$ few-body Glauber model calculation for $2s_{1/2}$ ($1d_{5/2}$) orbitals as a function of different ${}^{22}$O rms radii within uncertainty of the value quoted in Table .

Figure 3

(a) The red filled circles show $R_{\mathrm{rms}}^{m\left(\mathrm{Fermi}\right)}$, the dashed vertical line is $R_{\mathrm{rms}}^{m\left(\mathrm{HO}\right)}$, and the blue open squares are $R_{\mathrm{rms}}^m$ from Ref. [1]. The diamonds/squares/triangles are coupled-cluster calculations with a cutoff $\mathrm{parameter}=4.0/3.8/3.6$ fm${}^{-1}$, where the filled points are $R_{\mathrm{rms}}^m$ and the open points are proton rms radii, respectively. (b) The interaction cross section of ${}^A\mathrm{O}+\mathrm{C}$ as a function of the mass number. The red filled circles are present data, and the open squares are from Ref. [1]. The diamonds/squares/triangles are CC calculations with a cutoff $\mathrm{parameter}=4.0/3.8/3.6$ fm${}^{-1}$. The cross marks (open circles) show results from Ref. [27] (Ref. [28]).