Directional Correlation of Nuclear-Collision Probability for Aligned Beams of Deformed Nucleus

We could observe the directional correlation of the nuclear-collision probability between the direction of beam of deformed nuclei and the deformation axis for heavy-ion collisions at intermediate energies for the first time. The experiment was carried out at the HIMAC synchrotron and fragment-separator facility. Aligned nuclear beams of $^{10}$B were produced through the projectile fragmentation of 130$A$ MeV $^{11}$B primary beam on Be targets. By selecting the parallel momentum using the separator, negative or positive nuclear spin alignment of $^{10}$B relative to the beam axis were created. The ground state of $^{10}$B is considered to have a large prolate deformation of $\beta_2 \sim +0.8$. Using these aligned beams, the interaction cross sections were measured on a carbon target. The interaction probabilities were precisely obserbed as a function of longitudinal momentum of the secondary $^{10}$B beam. A clear directional correlation was observed. We will report on the details of measurements and discussions on this intriguing result.