Pairing dynamics and solitonic excitations in collisions of medium-mass, identical nuclei

Abstract

We present results of collisions of 90 Zr+ 90 Zr and 96 Zr+ 96 Zr obtained within time-dependent density functional theory (TDDFT) extended to superfluid systems, known as time-dependent superfluid local density approximation (TDSLDA). We discuss qualitatively new features occurring during collisions of two superfluid nuclei at energies in the vicinity of the Coulomb barrier. We show that a solitonic excitation-an abrupt pairing phase distortion-reported previously [P. Magierski et al., Phys. Rev. Lett. 119, 042501 (2017)], increases the barrier for capture generating effective repulsion between colliding nuclei. Moreover we demonstrate that pairing field leads to qualitatively different dynamics at the Coulomb barrier which manifests itself in a slower evolution of deformation towards compact system. Last but not least, we show that magnitude of pairing correlations can be dynamically enhanced after collision. We interpret it as a dynamically-induced symmetry breaking, which leads to large-amplitude oscillations of pairing field and bear similarity to the pairing Higgs mechanism.