Measurement of the net $\Lambda$ polarization in heavy-ion collisions from STAR

Non-central heavy-ion collisions provide a system with non-zero total angular momentum which can be transferred, in part, to the fireball via baryon stopping. It has been predicted that this angular momentum will lead to a net spin of emitted particles through coupling with the bulk material. Due to its parity violating decay the Λ is self-analyzing, which allows us to associate the daughter proton decay direction with Λ spin. Ultimately this allows us to use them as a probe of net-particle spin. I will present preliminary STAR measurements of the net Λ polarization from Au+Au collisions at 7.7, 11.5, 14.5, 19.6, 27, and 39 GeV.

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