ALPHA-CLUSTERS IN N=Z NUCLEI AND COHERENT EMISSION OF 2α- and 3α-CLUSTERS FROM EXCITED COMPOUND NUCLEI

Abstract

Conditions for a phase change with the formation of an α-particle condensate in excited N = Z nuclei, a dilute Bose-Gas, are discussed for excitation energies around EBα = 0, These are second order phase transitions in a mixed gas of Fermions and Bosons. The de-Broglie wavelength of relative motion for α-particles in these states is much larger then the nuclear radii. The experimental observation of the decay of such condensed α-particle states is proposed, with the coherent emission of several correlated α-particles, a decay not described by the Hauser-Feshbach approach for statistical compound nucleus decay. Examples of such observations with the enhanced emission of unbound resonances of 8 Be and [Formula: see text] — clusters are discussed. The experiments involved the ISIS-GASP-detection systems at the Laboratorii Nationale di Legnaro.