Study of highly excited states in 16O with 3He+13C reactions at low energies

Abstract

We report some preliminary experimental results on 13C(3He,α)12C reactions at low bombarding energies, in the range 1.4 – 2.2 MeV. The reconstruction of kinematic quantities in the final channel was performed by using a high-performance, low-threshold hodoscope, allowing for the particle identification even for low energy ejectiles. We succeeded in measuring detailed angular distributions, in absolute values, even for the transition leading to the emission of 12C in the Hoyle state, then resulting into 4 α particles in the final channel. The analysis of angular distributions as a function of energy suggests the occurrence of two low-spin resonant states, respectively with Jπ = 1− and 2+, at excitation energies of ≈ 24.1 and 24.5 MeV.