Shear induced polarization: Collisional contributions

Abstract

It has been realized that thermal shear plays a similar role as thermal vorticity in polarizing spin of particles in heavy ion collisions. We point out that shear has a fundamental difference that it leads to particle redistribution in the medium. The redistribution gives rise to an additional contribution to spin polarization through the self-energy, which is parametrically the same order as the one considered so far in the literature. The self-energy contribution is in general gauge dependent. We introduce double gauge links stretching along the Schwinger-Keldysh contour to restore gauge invariance. We also generalize the straight path to adapt to the Schwinger-Keldysh contour. We find another contribution associated with the gauge link, which is also parametrically the same order. We illustrate the two contributions with a massive probe fermion in massless QED plasma with shear. A modest suppression of spin polarization is found from the combined contributions when the probe fermion has momentum much greater than the temperature.

29 pages, 5 figures

References in corpus (7)

• Collective longitudinal polarization in relativistic heavy-ion collisions at very high energy
• Global quark polarization in non-central $A+A$ collisions
• Relativistic second-order dissipative spin hydrodynamics from the method of moments
• A hydrodynamic study of hyperon spin polarization in relativistic heavy ion collisions
• Quantum kinetic theory for dynamical spin polarization from QED-type interaction
• Spin evolution of massive fermion in QED plasma
• Massless Limit of Transport Theory for Massive Fermions

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