Breakup of Li6+p at near-barrier energies and the effect on elastic scattering

Abstract

Exclusive breakup measurements have been performed for the 6 Li + p system in inverse kinematics at 6 Li incident energies of 25 and 29 MeV. The results are considered in the Continuum Discretized Coupled-Channels framework, together with elastic scattering data at 16, 20, 25, and 29 MeV, obtained simultaneously in the same experiment and reported previously. Good agreement between data and theory is observed, interpreted as evidence for strong coupling to the continuum. The direct and sequential (via the 6 Li 3 1 + resonance) breakup cross sections are found to be equally large at the higher incident energies but the dominant effect on the elastic scattering is due to coupling to the sequential breakup. This effect remains dominant even at the lowest energy of 16 MeV, despite the negligible cross section for excitation of the resonance at this low incident energy.

Important role of projectile excitation in O16+Ni60 and O<

“…Notwithstanding, studies on it are commonly performed aiming to investigate the nucleus-nucleus potential or the effect of nonelastic channels. There are many examples in the literature where a detailed description of elastic scattering is essential to understand emerging phenomena, like the threshold anomaly on tighly [1][2][3] and weakly [4][5][6][7] bound nuclei, the break-up dynamics [8][9][10][11] and the nuclear rainbow [12][13][14][15].…”

Study of continuum excitation by light weakly bound projectiles on proton target

“…As an example, elastic scattering and breakup data for 6 Li + p system at the energy of 25 MeV are presented in Figure 2. Re-sults for the rest of the energies may be found in [7]. As it is seen, coupling to resonant breakup is the dominant one, while coupling to the non-resonant (direct) breakup has a minor effect on the reproduction of the elastic scattering data.…”

“…Having determined the efficiency of our detection system via code MULTIP, the angular distributions for the breakup of 6,7 Li on a proton target were deduced. The resulted breakup data together with the elastic scattering ones were analyzed within the CDCC framework following the prescription described in Refs.…”

“…The 6 Li and 7 Li beams were delivered by the TANDEM accelerator and impinged on a thin CH 2 target. For the elastic scattering measurement [4][5][6], the 6 Li ( 7 Li) ejectiles were detected by the MAGNEX spectrometer while, for the breakup measurement [6][7][8] the α-particles were measured in MAGNEX in coincidence with 2 H ( 3 H) measured in a silicon detector, appropriately masked by a tantalum foil to avoid elastic scattering deterioration. The angular range covered by MAGNEX was 0 o ≤θ lab ≤10 o , while for the silicon detector was 4 o ≤θ lab ≤6 o .…”

“…From the experimental point of view, is not always an easy task to obtain a clear signature of the breakup mechanism by studying energy spectra in singles, since due to their continuous shape they may interfere with events originating from different sources of background or with events triggered by a different reaction mechanism. Therefore, we have performed elastic scattering and exclusive breakup measurements with the weakly bound nuclei 6,7 Li on a proton target. Both data are considered into a CDCC framework.…”