Anomalous population ofHe10states in reactions withLi11

Abstract

Structure with the lowest energy observed in the 10 He spectrum populated in the proton knockout reaction with a 11 Li beam has a peak at 1.2 to 1.5 MeV. This peak is usually interpreted as a resonant 0 + ground state of 10 He. Our theoretical calculations indicate that this peak is likely to be a superposition of 1 − , 0 + , and 2 + excitations with very similar shapes. Moreover, the "soft" 1 − excitation appears to be the lowest in energy. Such an anomalous continuum response is traced to the halo structure of 11 Li providing an extreme low energy shift to all the expected continuum excitations. Competition between effects on the spectrum of the initial-state structure and of the final-state interaction and three-body correlations in 10 He are discussed. The analogous effect of an extreme low-energy shift could also be expected in other cases of 2n emitters populated in reactions with halo nuclei. A simplified example of the 10 He spectrum in α knockout from 14 Be is given. We also discuss limits on the properties of 9 He stemming from the observed 10 He spectrum.

Thomas-Ehrman effect in a three-body model: TheNe16case

“…WF Ψ17 Ne was obtained in [12] in a threebody 15 O+p+p model and different aspects of nuclear dynamics for this system were investigated in [13]. The WF of the removed neutron was constructed in the 14 O+n approximation for 15 O in such a way that the neutron separation energy and experimental matter radius of 15 O are reproduced, see Ref. [14] for details of the whole procedure.…”

Further insights into the reactionBe14(CH2,X)He10Jones1, Kohley2, Baumann3 et al. 2015Phys. Rev. C10010View full textAdd to dashboardCite

“…Figure 13 of Ref. [5] showed that such a calculation describes the 3-body decay energy from our experiment well. However, the calculations had not been folded with experimental resolutions and efficiencies.…”

“…This process was proposed in Ref. [5] in order to explain our decay energy spectrum. In addition, α removal has also been suggested to explain the population of 12 Be from a 55 MeV/nucleon 17 C beam incident on a beryllium target [26].…”

“…The α-removal 3-body distribution for 10 He was derived from the same model used to explain the removal from 11 Li as presented in Ref. [5]. In this model 14 Be is treated as a 12 Be core and two neutrons, with the 12 Be core considered as 8 He + α.…”

“…Earlier this year Sharov et al [5] suggested that our results could be explained by assuming that 10 He was populated directly by an α-cluster removal, thus again exhibiting a structure which is due to the halo-nature of the initial 14 Be.…”