Reactions of halo nuclei at energies around the coulomb barrier
I. Martel 1*
1 University of Huelva
Along the last few decades a large number of exotic nuclei have become available at low energies in a number of radioactive beam facilities like RIKEN (Japan), FLNR (Russia), REX-ISOLDE/CERN (Switzerland), CRC/LLN (Belgium), GANIL (France), TRIUMF (Canada) and RIBRAS (Brasil).
The case of low energy scattering of 6,8He systems with heavy targets have been extensively studied in the Cyclotron Research Center (Louvain-la-Neuve, Belgium) and in the SPIRAL facility at GANIL (Caen, France). The scattering of 11Be was studied at the REX-ISOLDE facility at CERN (Geneva, Switzerland), and very recent results on 11Li have just been obtained at TRIUMF facility (Vancouver, Canada).
These exotic light nuclei exhibit several dynamical effects whose are absent in the collision between normal stable nuclei [1,2]. The weakly bound structure of neutron haloes give rise to extended density distributions, producing strong couplings to dipole modes and continuum states at energies around the Coulomb barrier. In this scenario strong halo effects are observed in the elastic scattering, transfer, breakup and fusion reaction channels. A long-range absorption phenomenon dumps the typical Fresnel diffraction pattern characteristic of heavy ion elastic cross sections ([3-5]). Large yields of core-like fragments are observed as a consequence of break/transfer through coupling to continuum states. At sub-barrier energies the sequential two-neutron channel process can produce fusion enhancement [6-7].
In this contribution we discuss recent experimental results of fusion and reactions of the exotic nuclei 6,8He, 11Be and 9,11Li with heavy targets at energies around the Coulomb barrier. In order to make a comparison between different scattering systems specific scaling parameters are introduced which remove the effects due to different coulomb barriers and sizes of the systems being compared. In the case of elastic, breakup and fusion channels, a convenient parameterization in terms of simple dynamical quantities seems to reveal interesting features of the underlying dynamics of these systems [8-10].
1. L.F. Canto et al., Phys. Rep. 424, 1 (2006).
2. N. Keeley et al., Prog. Part. Nucl. Phys. 63, 396 (2009).
3. A. Sánchez-Benítez et al., Nucl. Phys. A 803, 30 (2008).
4. D. Escrig and et. al., Nucl. Phys. A 792, 02 (2007).
5. L. Acosta et al. Phys. Rev. C (2011), (submitted).
6. V.I. Zagrebaev, Phys. Rev. C 67, 061601 (2003).
7. S.M. Lukyanov et al., Phys. Lett. B 670, 321 (2009).
8. P.R.S. Gomes et al., Eur. Phys. Jour. (in this volume).
9. J. J. Kolata and E. F. Aguilera, Phys. Rev. C 79, 027603 (2009).
10. E.F. Aguilera et al., Phys. Rev. C 83, 021601(R) (2011)