Dissipative Reactions with Intermediate-Energy Beams: A Novel Approach to Populate Complex-Structure States in Rare Isotopes.

A novel pathway for the formation of multiparticle-multihole excited states in rare isotopes is reported from highly energy- and momentum-dissipative inelastic-scattering events measured in reactions of an intermediate-energy beam of ^{38}Ca on a Be target. The negative-parity, complex-structure final states in ^{38}Ca are observed following the in-beam γ-ray spectroscopy of events in the ^{9}Be(^{38}Ca,^{38}Ca+γ)X reaction in which the scattered projectile loses longitudinal momentum of order Δp_{||}=700  MeV/c. The characteristics of the observed final states are discussed and found to be consistent with the formation of excited states involving the rearrangement of multiple nucleons in a single, highly energetic projectile-target collision.

Publisher's Note: Direct Lifetime Measurements of the Excited States in ^{72}Ni [Phys. Rev. Lett. 116, 122502 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.116.

Extending the Southern Shore of the Island of Inversion to ^{28}F.

Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230  MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6)  keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60)  keV to be deduced.

Fragmentation of Single-Particle Strength around the Doubly Magic Nucleus ^{132}Sn and the Position of the 0f_{5/2} Proton-Hole State in ^{131}In.

Spectroscopic factors of neutron-hole and proton-hole states in ^{131}Sn and ^{131}In, respectively, were measured using one-nucleon removal reactions from doubly magic ^{132}Sn at relativistic energies. For ^{131}In, a 2910(50)-keV γ ray was observed for the first time and tentatively assigned to a decay from a 5/2^{-} state at 3275(50) keV to the known 1/2^{-} level at 365 keV. The spectroscopic factors determined for this new excited state and three other single-hole states provide first evidence for a strong fragmentation of single-hole strength in ^{131}Sn and ^{131}In.

Is the Structure of ^{42}Si Understood?

A more detailed test of the implementation of nuclear forces that drive shell evolution in the pivotal nucleus ^{42}Si-going beyond earlier comparisons of excited-state energies-is important. The two leading shell-model effective interactions, SDPF-MU and SDPF-U-Si, both of which reproduce the low-lying ^{42}Si(2_{1}^{+}) energy, but whose predictions for other observables differ significantly, are interrogated by the population of states in neutron-rich ^{42}Si with a one-proton removal reaction from ^{43}P projectiles at 81  MeV/nucleon. The measured cross sections to the individual ^{42}Si final states are compared to calculations that combine eikonal reaction dynamics with these shell-model nuclear structure overlaps.