Ponente
Abstract
In regions at the border of nuclear stability, the reduced binding energy can favour tunnelling of valence nucleons through the barrier, extending the nuclear density to large distances and forming the so-called “nuclear halos” [1,2].
In high-energy scattering (above 100 MeV/u) the collision process is more sensitive to the single-particle structure, and a neutron halo will produce a narrow momentum distribution of the breakup fragments and a large value of the interaction cross section. At low collision energies around the Coulomb barrier, the dynamics is dominated by collective degrees of freedom and is characterised by the coupling between the elastic, transfer and breakup channels, and the effects of the continuum. The weakly bound isotope 15C has been investigated in several experiments at high energies and the distribution of transverse-momentum for one-neutron breakup and the reaction cross sections, suggest the presence of a halo [3]. Due to the particular ground-state configuration, 15C would be unique nuclear system in exhibiting a pure 2s1/2 single neutron halo ground state [4].
In this contribution we present the first experimental results for the 15C+208Pb scattering system at E = 65 MeV, just around the Coulomb barrier. The experiment was performed at the ISOLDE radioactive beam facility at CERN and the measurement was carried out with the GLORIA detector array [5]. Details of the experiment and the first results of the elastic cross sections will be presented and discussed in the framework of coupled reaction channels calculations [6].
[1] I. Tanihata et al., Phys. Rev. Lett. 55,2676.
[2] P.G. Hansen, B. Jonson, Europhys. Lett. 4,409.
[3] A. Ozawa, Nucl. Phys. A 738,3844.
[4] G. Murillo, S. Sen, S.E. Darden, Nucl. Phys. A 579,125.
[5] G. Marquínez-Durán, Nucl. Inst. Meth. A 755,6.
[6] N. Keeley, K.W. Kemper and K. Rusek, Eur. Phys. J. A 50,145.
