Neutron halo effect on direct neutron capture and photodisintegration.

Abstract

A novel effect of the neutron halo formation is presented for the direct radiative neutron capture where a [ital p]-wave neutron is captured into an [ital s] orbit with neutron halo by emitting an [ital E]1 [gamma] ray. As an example, an enormous enhancement is demonstrated for the cross section of [sup 12]C([ital n],[gamma])[sup 13]C(1/2[sup +]) at low energy in excellent agreement with a recent experiment. The [ital S] factor of the final state is evaluated. The inverse process, i.e., photo disintegration is discussed for an example of [sup 11]Be. A sharp but nonresonant peak near the threshold is obtained as a result of the neutron halo in its anomalous ground state.