Speakers
Description
The Spin Hall Effect (SHE) is a generation of spin polarization for moving spin carriers in materials under an external electric field and is instrumental in investigating quantum effects in many-body systems [1]. Recent theoretical calculations indicate that the gradient of baryonic chemical potential (analogous to the electric field) can induce a sizeable spin Hall current in Au+Au collisions at $\sqrt{s_{NN}}$ $\sim$ 10 GeV. Furthermore, at the RHIC Beam Energy Scan (BES) energies, the sign as well as the pattern of energy dependence of the difference between the harmonics of spin polarization of $\Lambda$ and $\overline{\Lambda}$ hyperons, can be significantly different with and without the presence of baryonic spin Hall current [2-4].
In this talk, we will present the harmonic coefficients of $\Lambda$ hyperons' spin polarization ($P_{x} \sin(2\Delta\phi)$, $P_{y} \cos(2\Delta\phi)$, $P_{z} \sin(2\Delta\phi)$) as functions of transverse momentum, rapidity, and collision centrality in RHIC BES-II Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 14.6, 19.6, and 27 GeV. These measurements serve as the first experimental probe of the predicted baryonic SHE in heavy-ion collisions.
[1] Y. Kato el al., Science 306 (2004) 1910
[2] S. Liu et al., JHEP 07 (2021) 181
[3] B. Fu et al., Phys. Rev. Lett. 127 (2021) 142301
[4] B. Fu et al., arXiv: 2201.12970 (2022)
| Present via | Online |
|---|
