Correlated two-proton decay from ${}^{10}\mathrm{C}$

The decay of ${}^{10}\mathrm{C}$ excited states to the $2p+2\alpha$ exit channel has been studied using inelastic excitation of a secondary ${}^{10}\mathrm{C}$ beam. The decay sequences leading to the $2p+2\alpha$ final state are determined for the previously known levels and for a newly found level at $E^{*}=8.4$ MeV. A state at $E^{*}=6.57$ MeV is shown to undergo two-proton decay to ${}^8{\mathrm{Be}}_{\mathrm{g}.\mathrm{s}.}$ with strong $p$-$p$ correlations consistent with the ${}^1\mathrm{S}$ phase shift. Based on the lack of such correlations for other two-proton decays, this indicates that the correlations are associated with structure of the parent level.

Figure 1

Level scheme and decay paths for ${}^{10}\mathrm{C}$.

Figure 2

Reconstructed excitation energies from two- and three-body correlations (left side, a–d) and four-body correlations (right side, e–i). Panels (c) and (d) exclude events with the ${}^8{\mathrm{Be}}_{\mathrm{g}.\mathrm{s}.}$ correlation. The $p{+}^9{\mathrm{B}}_{\mathrm{g}.\mathrm{s}.}$ detection efficiency is included, with an internal axis, in panel (f).

Figure 3

Three-particle ($\alpha \alpha p)$ versus four-particle energy correlations showing a new state in ${}^{10}\mathrm{C}$ at $E^{*}=8.4$ MeV that decays through the 2.361 MeV state in ${}^9\mathrm{B}$.

Figure 4

Energy (left) and angle (right) $p$-$p$ correlations for the 5.30 (top) and 6.57 MeV (bottom) structures. The data are the combined data from the present and previous [14] experiments. Simulations for decay uniformly spanning the full three-body phase space (thick lines) and correlated $2p$ emission calculated using the $R$-matrix formalism (thin lines) are shown. The dotted lines are mixtures of three-body and correlated (85:15 and 35:65 for the 5.30 and 6.57 MeV states, respectively.) The dashed line (b) is the Faddeev calculation discussed in the text.