Fusion and direct reactions for the system<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>6</mml:mn></mml:msup></mml:math>He<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mo>+</mml:mo></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>64</mml:mn></mml:msup></mml:math>Zn at and below the Coulomb barrier

Fusion and transfer $+$ breakup channels have been studied in the collision induced by the two-neutron-halo ${}^{6}$He on a ${}^{64}$Zn target at energies from below to above the Coulomb barrier. For comparison, the reaction induced by the stable isotope ${}^{4}$He on the same target has been studied. The fusion cross section has been measured by using an activation technique, detecting off-line the delayed x-ray activity following the electron capture decay of the evaporation residues. New measurements of the ${}^{4}$He $+$ ${}^{64}$Zn fusion cross section at sub-barrier energies have been performed in order to cover the same energy range of the ${}^{6}$He $+$ ${}^{64}$Zn fusion cross section and to compare the excitation functions for the two systems down to the lowest energy data point measured for ${}^{6}$He. From the new comparison a sub-barrier fusion enhancement has been observed in the ${}^{6}$He case with respect to the ${}^{4}$He one whereas no effect on the ${}^{6}$He fusion cross section has been seen at energies above the barrier. It has been concluded that such enhancement seems to be due to the diffuse halo structure properties of the ${}^{6}$He nucleus. Moreover, the reactions induced by ${}^{6}$He have shown a strong yield of $\ensuremath{\alpha}$ particles coming from direct processes.