An experimental way of testing Bose-Einstein condensation of alpha clusters in the atomic nucleus is reported. The enhancement of cluster emission and the multiplicity partition of possible emitted clusters could be direct signatures for the condensed states. The barrier for the emission of clusters, such as (8)Be and (12)C(O(+)(2)), is calculated and compared with the barrier for the sequential emission of 2 or 3alpha particles from the compound nucleus. For the calculations, a simple approach using a folded Woods-Saxon potential is used.

The two-neutron transfer reaction 9 Be( 16 O, 14 O) 11 Be[ 10 Be + n] has been used to measure the branching ratios for the neutron decay of excited states of 11 Be. The 14 O ejectile was detected by a Q3D spectrometer at forward angles. The energies and angles of the 10 Be fragments of the decaying 11 Be * recoil were measured in coincidence with the 14 O ejectile using a double-sided silicon strip detector array at backward angles. This enabled a kinematic reconstruction of the reaction to be performed. Theoretical decay branch ratios were calculated using barrier penetrability factors and were compared to the measured ratios to provide information on the relative reduced widths of the states. The decay widths have been used to link states in 11 Be with a common structure and structurally to states in the daughter nucleus 10 Be. The 3/2 − 8.82-MeV state was identified as a candidate for a molecular band head.

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