Study of the elastic scattering of 6He on 208Pb at energies around the Coulomb barrier

Abstract

The elastic scattering of 6He on 208Pb has been measured at laboratory energies of 14, 16, 18 and 22 MeV. These data were analyzed using phenomenological Woods- Saxon form factors and optical model calculations. A semiclassical polarization po- tential was used to study the e ect of the Coulomb dipole polarizability. Evidence for long range absorption, partially arising from Coulomb dipole polarizability, is reported. The energy variation of the optical potential was found to be consistent with the dispersion relations which connect the real and imaginary parts of the potential

He6breakup dynamic polarization potential reexamined

“…[9], relating to 6 He on 208 Pb at energies around the Coulomb barrier, that the radial range of sensitivity lies much further within the overlap region for the real part than it does for the imaginary part.…”

“…Although the global deuteron potential used as a surrogate for the 2n + 208 Pb optical potential does have energy-dependent real and imaginary well depths, ignoring this dependence leads to physically reasonable results in this case. As evidence of this, the full CDCC calculation gives a good description of the 22 MeV 6 He + 208 Pb elastic-scattering data [9]. To study the specific contribution of the 2 + resonance at 1.8 MeV, we also performed CDCC calculations that include only the coupling to this state.…”

“…It is of interest to examine the DPP closer to the Coulomb barrier and for this reason we repeated the Moro-model calculations, with full continuum couplings, at 22 MeV, an energy for which there are elastic-scattering data [9]. To establish whether the resulting energy dependence continued to higher energies, we also established the DPPs at 32 MeV.…”

Simultaneous analysis of the elastic scattering and breakup channel for the reactionLi11+Pb208at energies near the Coulomb barrier

“…This occurs, for example, in collisions of 11 Li with a heavy target nucleus. At energies around and below the Coulomb barrier, where nuclear effects are expected to be small, this phenomenon, known as dipole Coulomb polarizability, produces a strong reduction of the elastic cross section with respect to the Rutherford prediction [13][14][15][16]. Moreover, the distortion of the projectile nucleus may lead to its dissociation, hence these experiments are usually accompanied by large breakup cross sections.…”

“…Recent advances in low-energy beam intensities in radioactive ion beam (RIB) facilities have allowed us to study these phenomena for several exotic nuclei, such as 6 He [14][15][16][17][18][19], 11 Be [20,21], and 11 Li [22,23] (see also Ref. [24] and references therein).…”