Research on the deformed halo in 29 F with a complex momentum representation method.

The weakly bound nucleus 29F locates near the neutron drip line. Experiments have confirmed that it is the heaviest two-neutron halo nucleus discovered up to now. To understand the halo structure in 29F, we explore the weakly bound and resonant levels close to the Fermi surface with the complex momentum representation method. Not only the narrow resonances and the broad resonances. Since the broad resonance 2 p 3/2 is disclosed, the p âˆ' f inversion and N = 20 shell gap quenching are found. The last valence neutron can occupy the weakly bound level 1/2[310], composed mainly of p 3/2â€"component, or the 1/2[211], composed mainly of s 1/2â€"component. Since the wavefunctions of p and s â€"components extend to a large range in the coordinate space, which results in the density distributions of the levels 1/2[310] and 1/2[211] being considerably diffuse. This is the most likely cause of halo formation in 29F and the halo may be formed by the p â€"component, s â€"component, or their mixtures by pairing correlations. [ABSTRACT FROM AUTHOR]