Search for cluster effects in p+12C elastic scattering by a diffractional method

Abstract

We investigate medium-energy angular distributions data of proton elastic scattering on $^{12}$C, with the aim to probe the existence of cluster distributions in the ground state of $^{12}$C. In our approach, we exploit Coupled-Channel calculations to describe the scattering from a spheroidal-like structure, and we include a further contribution, based on a diffraction scattering formula, to explicitly take into account a possible triangular $\alpha$-cluster structure of the target. From the present analysis, we find a quite small cluster component in $^{12}$C ground state (with an upper limit on the occurrence probability of $1\%$, $99.75\%$ confidence level) and an inter-cluster distance of $\simeq 3.9$ fm. These values are compared with several theoretical predictions reported in the literature.