The Hoyle Family: break-up measurements to probe α-condensation in light nuclei

Abstract

The ^{12}12C Hoyle state is a candidate for \alphaα-condensation, due to its large volume and \alphaα-cluster structure. This paper discusses precision break-up measurements and how they can elucidate \alphaα-condensate structures. Two experiments are discussed in detail, firstly concerning the break-up of ^{12}12C and then the decays of heavier nuclei. With more theoretical input, and increasingly complex detector setups, precision break-up measurements can, in principle, provide insight into the structures of states in \alphaα-conjugate nuclei. At present, such searches have not delivered evidence for \alphaα-condensation in ^{12}12C or ^{16}16O.

Stringent upper limit on the direct 3α decay of the Hoyle state in C12

“…Including a more realistic Coulomb interaction for overlapping spherical charge distributions, rather than point charges, will affect the result. However, this has previously been evaluated for the sequential decay of the Hoyle state and was found to give a modest change for reasonable R 0 values [33]. Furthermore, the inclusion of an attractive nuclear potential will act to lower the tunneling barrier near to the channel radius, thus altering the absolute values of the decay penetrability.…”