1. Nuclear Physics Seminar

"Global and local polarization of Lambda hyperons in Au+Au collisions"

Presented by Takafumi Niida

Tuesday, February 4, 2020, 11 am
Small Seminar Room, Bldg. 510

Hosted by: Rongrong Ma

The matter created in non-central heavy-ion collisions is expected to have an initial angular momentum carried by two colliding nuclei. Such an initial angular momentum would be transferred to the global polarization due to the spin-orbit coupling. The STAR Collaboration observed \Lambda global polarization in Au+Au collisions at \sqrt{s_{NN}} = 7.7—200 GeV, indicating a thermal vorticity of the system. The detailed structure of the vorticity field may be complicated. Local vorticity and consequently the particle polarization may arise from jets and/or collective flow. In this talk, recent results on the polarization along the beam direction expected from the elliptic flow will be presented and the physics implications will be discussed with theoretical calculations.