ALPHA-CORRELATIONS IN NUCLEI

G. RIPKA
1971 Le Journal de Physique Colloques  
RBsum6. -On suppose que les etats excites selectivement dans les reactions de transfert-a ont de fortes corrClations-a definies comme une corrdation spatiale entre les nuclkons. On discute les mod⩽ susceptibles d'expliquer ces corrblations. On montre comment la mesure des energies des orbites peut determiner la repulsion dans les Btats p qui est responsable de cette correlation. Abstract. -It is conjectured that the states which are selectively excited in a-transfer reactions have strong
more » ... lations, defined as a spatial correlation between nucleons. It is shown how present nuclear models can account for these. It is shown how saturation properties and the energies of single particle orbits can determine the amount of p-state repulsion responsible for a-clustering. I. Introduction. -One of the objectives of this conference is to determine what the selectivity of a-transfer experiments can teach us about a-correlations in nuclei and whether the theory can account for such correlations. The early experiments in which an a-particle was transferred to the light nuclei of the I p and of the 2s-Id shell by means of ( 6~i , d) and (7Li, t) reactions [I], [2] showed that these reactions excited preferentially deformed ground and excited rotational bands. These rotational bands could be understood either in terms of SU3 theory, Hartree-Fock theory or the a-cluster model. Later, a-transfer reactions were performed by means of (160, 12C) reactions on medium weight nuclei of the 2p-lf shell in the Ni and Zn region 131. The theoretical interpretation of the levels excited in these nuclei is faced with a double problem : the levels are not identified and the models used for l p and 2s-Id shell nuclei no longer work in the 2p-lf shell. In this contribution we shall define the a-correlations, show why they occur and illustrate them in the various nuclear models. We shall also show how a-correlations are related to the saturation properties of the nuclear force. Finally we shall discuss the successes and failures of the nuclear models when confronted with experimental data.
doi:10.1051/jphyscol:1971660 fatcat:4hk3ivchlrgm5fdjej5utbylei