Speaker
Description
In relativistic heavy-ion collisions, the relative motion of heavy quarkonium with respect to the quark-gluon plasma (QGP) induces spin alignment. Our previous work attributed this to a repopulation of quarkonium's spin components, an effect rooted in the spin degree of freedom. Here we reveal a complementary mechanism, which operates at the orbital level: the relative motion between $Q\bar{Q}$ and the medium gives rise to a corrected complex potential between heavy quarks. Such a complex potential deforms the wave function through a D-wave admixture, thereby contributing to the observed spin alignment. By treating Debye mass $m_D$ as a free parameter, we find that as $m_D$ decreases, more D-wave continuum states turn into bound states, enhancing the spin alignment. Expanding the relative velocity to $O(v^2)$, we calculate the resulting spin alignment.
