C12+C12elastic scattering excitation functions and phase shift analysis

Abstract

The $^{12}\mathrm{C}$+ $^{12}\mathrm{C}$ elastic scattering has been measured for ${E}_{\mathrm{c}.\mathrm{m}.}=14.6\ensuremath{-}31.3$ MeV, ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}=30\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}110\ifmmode^\circ\else\textdegree\fi{}$. The elastic data have been analyzed via a phase shift analysis, enabling the extraction of model independent sets of phase shift parameters. The extracted ${J}^{\ensuremath{\pi}}$ values for the intermediate structure resonances at ${E}_{\mathrm{c}.\mathrm{m}.}=18.4, 19.3, \mathrm{and} 20.3$ MeV are ${12}^{+}$, ${12}^{+}$, and ${12}^{+}$ or ${14}^{+}$, respectively. The questions of ambiguities in the phase shift analysis and the comparison with ${J}^{\ensuremath{\pi}}$ values deduced from other experiments are discussed. Evidence is presented for the existence of gross structure resonances. The elastic scattering has also been analyzed using the sum-of-differences method to directly extract the total reaction cross section. The results of these analyses are compared to existing models of the origin of intermediate structure resonances.NUCLEAR REACTIONS Measured the $^{12}\mathrm{C}$+ $^{12}\mathrm{C}$ elastic scattering, ${E}_{\mathrm{c}.\mathrm{m}.}=14.6\ensuremath{-}31.3$ MeV, ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}=30\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}110\ifmmode^\circ\else\textdegree\fi{}$. Phase shift analysis, sum-of-differences analysis.