Fusion of halo nucleus 6He on 238U : Evidence for tennis-ball (bubble) structure of the core of the halo (even the giant-halo) nucleus

Abstract

In a decade-and-a-half old experiment, Raabe et al. [Nature 431, 823 (2004)], had studied fusion of an incoming beam of halo nucleus 6He with the target nucleus [Formula: see text]. We extract a new interpretation of the experiment, different from the one that has been inferred so far. We show that their experiment is actually able to discriminate between the structures of the target nucleus (behaving as standard nucleus with density distribution described with canonical RMS radius [Formula: see text] with [Formula: see text] fm), and the “core” of the halo nucleus, which surprisingly, does not follow the standard density distribution with the above RMS radius. In fact, the core has the structure of a tennis-ball (bubble)-like nucleus, with a “hole” at the center of the density distribution. This novel interpretation of the fusion experiment provides an unambiguous support to an almost two decades old model [A. Abbas, Mod. Phys. Lett. A 16, 755 (2001)], of the halo nuclei. This Quantum Chromodynamics based model succeeds in identifying all known halo nuclei and makes clear-cut and unique predictions for new and heavier halo nuclei. This model supports the existence of tennis-ball (bubble)-like core, of even the giant-neutron halo nuclei. This should prove beneficial to the experimentalists, to go forward more confidently, in their study of exotic nuclei.