Alpha particle condensation in nuclear systems

Abstract

The second 0+ state at 7.65 MeV in 12C is the famous Hoyle state, very important in Nuclear Astrophysics for synthesizing 12C in the universe. This state is known to strongly resist a shell model description. Describing it as a loosely bound gas of alpha particles, i.e. actually an alpha particle condensate, with a microscopic 12‐nucleon wave function, we obtain with no adjustable parameter energy position and inelastic form factor correctly. It is shown that the 22+ state, which was recently observed and is located at 2.6 MeV above the 3α threshold, has a structure similar to the Hoyle state of Bose‐condensate character with a dilute 3α gas‐like structure. It is also reported that in 16O the recently observed 0+ state slightly below the 4α threshold is preferably assigned to the 4α condensed state.