Exclusive and restricted-inclusive reactions involving the 11Be one-neutron halo

One-neutron knockout from light neutron-rich nuclei at relativistic energies

“…The enhanced cross sections can be understood as a direct consequence of the weaker binding energies and significant 1s 1/2 admixtures, where the core levels are completely filled up to 0d 5/2 and there is a single neutron in a 1s 1/2 orbit. This effect was reported earlier for 23 O and 24 F in Refs. [44,49].…”

“…In particular, the interest in one-nucleon knockout reactions was triggered in the mid-1980s by the study of halo nuclei [23][24][25][26][27][28][29]. In the context of one-neutron halos, the weak binding of the valence neutron causes a significant increase of the one-neutron knockout cross section and the emerging A − 1 fragments exhibit narrow momentum distributions that reflect the spatial extension of the halo.…”

“…Structural phenomena such as the formation of one-neutron halos in odd-mass carbon isotopes ( 15,17,19 C) will be discussed. In addition, one-neutron knockout measurements from 22 N were carried out for the first time and demonstrate clearly the change from a 0d 5/2 to a 1s 1/2 orbital for the valence neutron, an effect that is expected above N = 14 and that was also observed in 23 O and 24 F. The possibility of an anomalous structure of 26 F, due to a significant 1s 1/2 neutron admixture, will also be discussed in the light of the experimental data obtained in this work. Finally, the ground-state configuration of neutron-rich neon isotopes ( 24−28 Ne) was studied, providing new information in a region that is relatively close to the island of inversion.…”

Nucleosynthesis: What Direct Reactions Can Do for It?

“…In contrast to this, the transverse distributions of the core are significantly broadened by diffractive effects and by Coulomb scattering. For experiments that observe the nucleon produced in elastic breakup, the transverse momentum is entirely dominated by diffractive effects, as illustrated [38] by the angular distribution of the neutrons from the reaction 9 Be( 11 Be, 10 Be+n)X. In this case, the width of the transverse momentum distribution reflects essentially the size of the target [39].…”

Nuclear physics in the cosmos

“…In contrast to this, the transverse distributions of the core are significantly broadened by diffractive effects and by Coulomb scattering. For experiments that observe the nucleon produced in elastic breakup, the transverse momentum is entirely dominated by diffractive effects, as illustrated [77] by the angular distribution of the neutrons from the reaction 9 Be( 11 Be, 10 Be+n)X. In this case, the width of the transverse momentum distribution reflects essentially the size of the target [78].…”