New Measurement of ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ Fusion Reaction at Astrophysical Energies

Carbon and oxygen burning reactions, in particular, ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion, are important for the understanding and interpretation of the late phases of stellar evolution as well as the ignition and nucleosynthesis in cataclysmic binary systems such as type Ia supernovae and x-ray superbursts. A new measurement of this reaction has been performed at the University of Notre Dame using particle-$\gamma$ coincidence techniques with SAND (a silicon detector array) at the high-intensity 5U Pelletron accelerator. New results for ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion at low energies relevant to nuclear astrophysics are reported. They show strong disagreement with a recent measurement using the indirect Trojan Horse method. The impact on the carbon burning process under astrophysical scenarios will be discussed.

Figure 1

The total $S^{*}(E)$ factor for this work is shown and compared with previous direct measurement data [22, 23, 24, 26, 27, 29, 32, 33, 34].

Figure 2

A coincidence spectrum (bottom) for a typical run at ${\mathrm{E}}_{\mathrm{beam}}=8.9\mathrm{MeV}$ between charged particles and $\gamma$ rays is shown. The middle panels show the projections to the $\gamma$ energies and the Doppler effects for the $p_1$ (left) and ${\alpha }_1$ (right) channels, respectively, where the bump just outside the ${\alpha }_1$ shaded region is contributed from the $p_2$ channel. The top panels present the similar projections for the lowest energy at ${\mathrm{E}}_{\mathrm{beam}}=4.4\mathrm{MeV}$.

Figure 3

The $p_1$ channel $S^{*}(E)$ factor for this work is shown and compared with previous work [5, 23, 33].

Figure 4

The ${\alpha }_1$ channel $S^{*}(E)$ factor for this work is shown and compared with previous work [5, 23, 33].