Global descriptions and decay rates for continuum excitation of weakly bound nuclei

Abstract

In this work we will present an overview of our global studies on continuum excitations induced by protons, for the weakly bound nuclei 6 Li, 7 Li and 9 Be, presenting strong clustering modes. Measurements are made in inverse kinematics and extensive simulations have been developed, to corroborate the analysis and interpretation of the results. The focus of the measurements is on the breakup reaction, but simultaneously this research is complemented by the study of all involved reaction channels, including elastic scattering. In this respect our theoretical interpretation in a Continuum Discretized Coupled Channel approach can be fully validated. Between our sound conclusions we can underline the following: the non reciprocity between the strengths of the breakup probability and the coupling to continuum; the experimental validation of a continuum discretization for three body Continuum Discretized Coupled Channel theories; and last but not least the unique possibility for deducing continuum decay rates of borromean nuclei in proton induced studies, by considering the kinematics of the target recoil. Other specific conclusions for each system will be discussed.

Global study of Be9 + p at 2.72A MeV

“…For the breakup measurement we followed the technique applied before in similar experiments [15,16,21,22] with MAGNEX, used to detect one of the α's in an almost full angular range namely θ lab = 2.5 • to 12 • . The elastically scattered 9 Be ions were most of them swept out by appropriate magnetic fields, allowing the detection of alphas in the energy range 6 to 9.5 MeV corresponding, according to our simulation [22,53], to the full energy phase space (see Fig. 1).…”

“…Our theoretical framework will be also applied to higher energy elastic scattering data at 5.67 A MeV, collected under similar experimental conditions [19][20][21]. In this respect our theory can be validated in a more global context and fruitful comparisons can be deduced.…”

“…Our first results, related with 6,7 Li exhibiting a two body cluster structure (α +d (t)), include not only elastic scattering [13,14] and breakup measurements [15,16], but also cross sections of all involved reaction channels [17,18]. In this respect a global description into a three -body Continuum Discretized Coupled Channel (CDCC ) framework was successfully obtained.…”

“…Measurements were made at low energies ≈ 6 times the Coulomb barrier. Recently at similar energies, we have measured the elastic scattering and breakup of a three -body cluster structure nucleus (α + α + n), the Borromean nucleus 9 Be, at 5.67 A MeV [19][20][21][22]. Decay rates were determined for the 2.429 ( 5/2 − ) MeV resonance of 9 Be into three decay modes, 5 He + 4 He, 8 Be + n and α + α + n, and a total breakup cross section was deduced.…”

Study of the 4He(4He,4He)4He* inelastic scattering at the MAGNEX facility

“…The experimental inelastic scattering data collected by the two coincidence measurements were compared with kinematical simulations based on the multipurpose Monte Carlo simulation algorithm MULTIP [16]. This algorithm is a powerful tool for two -, three -and four -body reactions kinematics and its validity has been tested in several works and for many reactions [17][18][19][20][21][22][23][24]. In the present work, the inelastic scattering reaction 4 He + 4 He → 4 He + 4 He * → 4 He + 3 H + 1 H was simulated for both the resonant (0 + ) and the non -resonant breakup, while the 4 He + 4 He → 4 He + 4 He * → 4 He + 3 He + n was simulated only for the non -resonant breakup since its threshold is higher than the 0 + resonant region.…”