First observation of α-cluster states in the 14O+4He interaction

We measured 14O+4He excitation functions for elastic scattering which demonstrate, for the first time, a well developed α-cluster structure in the proton rich nucleus, 18Ne. We present the excitation energies and estimates of the spins for the dominant resonances using an R-matrix approach. A resonance at 9.2 MeV excitation energy in 18Ne is particularly interesting. The spin-parity of the state is found to be 3- and the α particle reduced width for the state appears to be comparable to the single particle limit. We have found indications for unusually large size of the observed α-cluster configuration.