| 研究開始時の研究の概要 |
The research aims at understanding the transport properties of elementary particles like quarks and gluons such as their diffusion of charges and polarization of spins in a rotating plasma phase created in heavy-ion-collision experiments. In such a system, the strongest fluid vorticity in our universe could be generated in the subatomic scale, which yields the polarization of quarks and gluons via quantum effects such as the chiral anomaly and spin-orbit interaction. This research may reveal detailed mechanisms and unexpected phenomena in relativistic spintronics in subatomic swirls.
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| 研究実績の概要 |
As mentioned in the proposal, we aim at exploring how the chiral anomaly, spin-orbit interaction, and related quantum effects affect “the intertwined charge/spin transport of quark gluon plasma (QGP) and of the pre-equilibrium phase in heavy ion collisions. One of the important purposes is to understand how the spin of quarks and also of gluons are dynamically polarized by vortical or electromagnetic fields and their contributions to experimental observables.
To track dynamical spin polarization particularly triggered by the collisional processes with spin-orbit interaction, it is necessary to modify the standard kinetic theory. By utilizing the Wigner-function approach, we have derived a generic formalism of the quantum kinetic theory (QKT) for massive fermions with quantum corrections in the collision term characterized by self energies, which paves the way to study dynamical spin polarization of a strange quark traversing the QGP. Such a collision term contains the quantum correction led by self-energy gradients, from which the spin polarization could be induced by space-time inhomogeneity of the medium such as local vorticity, as the generalization for side-jump corrections upon massless fermions in the previously derived chiral kinetic theory. In addition to the study of fermions, we have also constructed the QKT for photons, which could be directly generalized to that for weakly coupled gluons. Moreover, we have studied how local vorticity could affect not only spin polarization of hadrons but also the yields for hadrons with different spins.
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