Experimental study of 8He + p elastic and inelastic scattering

Low-lying states and structure of the exotic 8He via direct reactions on the proton

“…A new resonance, at 5.4 ± 0.5 MeV with an intrinsic width Γ = 0.5 ± 0.3 MeV was found [13], in addition to the known resonance 2 + 1 that we observed at 3.62 ± 0.14 MeV (Γ = 0.3 ± 0.2 MeV). The 2 + 1 state is consistent with the previous data obtained by (p,p') [7], multi-nucleon transfer [14,15] or break-up [16] reactions, and in constrast with the data in [17]. The resonances predicted by the ab-initio QMC calculations [3] or the ab-initio NCSM [18] are not in agreement with our results, as shown in Fig.…”

“…The areas drawn for each resonance correspond to the FWHM widths. 7 He was also extracted from the 8 He(p,d) reaction. The analysis is discussed in [11].…”

“…It is a powerful probe to investigate the ground state (gs) and transition densities to excited states of the light exotic nuclei, as shown by the recent results obtained on the halo of 6 He [1]. Previous 8 He(p,p') data exist; the (p,p') was measured at RIKEN [7] and a 2 + resonance was observed at 3.57±0.12 MeV (width Γ = 0.5 ± 0.35 MeV). But the low statistics and reduced angular range for the (p,p') distributions did not allow to perform a detailed microscopic analysis of the density profiles, as done for 6 He in [1].…”

“…The (p,p') scattering to the 2 + 1 state, the (p,d) 7 He and (p,t) 6 He transfer reactions, were measured at the energy E lab = 15.7 A.MeV. The light charged particles (p,d,t) were detected in the MUST Si-strip telescope array.…”

Spin observable in proton elastic scattering of6He and its relevance to cluster structure

“…Recently the proton elastic scattering studies are applied for light neutron-rich nuclei [1,2,3]. A major goal of the studies is to determine matter distributions, more specifically neutron distributions, in the neutron-rich nuclei and to argue existence of halo and/or skin structures.…”