Speaker
Description
Spin correlation is believed to be a significant contribution to vector meson spin alignment. In this work, we study the generation of spin correlation through fluctuations of the chromomagnetic field in the quark-gluon plasma medium. We show that anisotropic fluctuations generically lead to finite spin alignment of vector mesons. We study two sources of anisotropic chromomagnetic field fluctuations: one comes from the motion of a vector meson with respect to the medium, with the boosted isotropic fluctuations in the medium turning into anisotropic ones in the vector meson's frame. The other comes from the shear flow of the QGP, with the anisotropy arising from viscous corrections to the gluon distribution function. We apply these mechanisms to study the spin alignment of J/ψ in the QGP. The chromofield correlators are evaluated using hard-thermal-loop (HTL) spectral functions. We find that the motion-induced contribution gives rise to negative spin alignment in the forward-rapidity region, while the shear-induced contribution is subleading. The mechanism is also expected to make a significant contribution to the spin alignment of ϕ.
