Classification of ${}^{20}\mathrm{F}$ states below 4.4 MeV

Angle-integrated cross sections and forward/backward ratios for the reaction ${}^{18}\mathrm{O}({}^3\mathrm{He},p){}^{20}\mathrm{F}$ have been combined with existing information in order to classify ${}^{20}\mathrm{F}$ states up to 4.4 MeV excitation. Experimental counterparts are now known for all 13 ${\left(sd\right)}^4$ shell-model states in this region.

Figure 1

Differences between present excitation energies and those from the compilation [1] are plotted vs excitation energy. Uncertainties from the compilation are displayed whenever they are larger than the data points. The rms average of the difference is 1.3 keV.

Figure 2

Ratio of forward (0–90 degrees)/backward (90–180 degrees) cross sections for the reaction ${}^{18}\mathrm{O}({}^3\mathrm{He},p){}^{20}\mathrm{F}$ is plotted vs excitation energy. The dashed band encompasses levels with $f/b\sim 1$.

Figure 3

From Ref. [12], the ratio of experimental to DWBA cross sections vs excitation energy for seven $sd$-shell states. Set I and Set II refer to different optical-model potentials [12].

Figure 4

Total cross sections (0–180 degrees) divided by $2J+1$ are plotted vs forward/backward ratios.

Figure 5

Forward/backward ratios for six states (listed in Table 2) that have a small direct component.

Figure 6

Forward/backward ratios plotted vs $2J+1$.

Figure 7

The left-hand column contains all the ${\left(sd\right)}^4$ shell-model states up to 3.8 MeV [31], listed by excitation energy and $J$. The right-hand column contains experimental states identified as ${\left(sd\right)}^4$ by Ref. [12] and herein.