The experimental evidence for the α Boson gas state in the
11C+12C→23Mg∗ fusion evaporation reaction is
presented. By measuring the α emission spectrum with multiplicity 2 and
3, we provide insight into the existence of a three-body force among α
particles. The observed spectrum exhibited distinct tails corresponding to
α particles emitted in pairs and triplets consistent well with the
model-calculations of AV18-UX and chiral effective field theory of NV2-3-la*,
indicating the formation of α clusters with three-body force in the
Boson gas state.Comment: 7 pages, 6 figure