Dynamical induced quark spin polarization by magnetic field at the early stage of heavy-ion collisions

TL;DR

This paper investigates how magnetic fields induce quark spin polarization during the early stages of heavy-ion collisions, highlighting the role of quark interactions and quantum corrections in the process.

Contribution

It introduces a detailed analysis of quark spin polarization dynamics using chiral kinetic theory, emphasizing the impact of quark interactions and quantum effects on electromagnetic response.

Findings

Quark interactions delay the decay of initial spin polarization.

Interactions accelerate the decay of later spin polarization.

Early-stage QGP exhibits incomplete electromagnetic response, differing from Lenz's law.

Abstract

We present a comprehensive analysis of the dynamic process of quark spin polarization induced by magnetic fields at the pre-thermal stage in heavy-ion collisions by using the recently developed theoretical tool of chiral kinetic theory. Our findings demonstrate that the spin polarization of quarks is highly sensitive to the interactions between quarks. These interactions can delay the decay of early spin polarization vector while accelerating the decay of later spin polarization vector. Specifically, our simulations show the detailed process of how magnetic fields polarize quarks within the fireball and reveal that quark interactions lead to an acceleration effect on the average spin. Notably, the fireball of quark-gluon plasma (QGP) in its early stages exhibits an incomplete electromagnetic response effect, which differs from the response predicted by Lenz's law. This discrepancy arises from quantum corrections involving the interactions between quark spin and electromagnetic fields.