Search for alpha-cluster state in ²⁰Ne

We searched for a state consisting of many α clusters in ²⁰Ne excited state.
Ikeda and collaborators predicted that α cluster state exists near the threshold of decay to nα. Experimentally, up to the 3 α cluster state of ¹²C has been confirmed so far. ²⁰Ne is a candidate for 5 α state with Z = 10 and N = 10. 

Results of an experiment on the emulsion exposure to medium-heavy nuclei of a few GeV have been reported. In this experiment, events that collapse into a number of α particles have been observed. The characteristic of these events is that the relative momentum of released alpha particles relative to the incident nuclei is very small and the momentum transfer to incident particles is small. We considered that this reaction might be excitation of an alpha-cluster state by Coulomb excitation by heavy nuclei in the emulsion.

The experiment has been carried out at NewSUBARU electron storage ring facility with an incident laser Compton scattering (LCS) photon beam and the active gas target MAIKo.