학술논문
Global Polarization of Ξ and Ω Hyperons in Au+Au Collisions at sNN=200 GeV
Document Type
article
Author
Adam, J; Adamczyk, L; Adams, JR; Adkins, JK; Agakishiev, G; Aggarwal, MM; Ahammed, Z; Alekseev, I; Anderson, DM; Aparin, A; Aschenauer, EC; Ashraf, MU; Atetalla, FG; Attri, A; Averichev, GS; Bairathi, V; Barish, K; Behera, A; Bellwied, R; Bhasin, A; Bielcik, J; Bielcikova, J; Bland, LC; Bordyuzhin, IG; Brandenburg, JD; Brandin, AV; Butterworth, J; Caines, H; de la Barca Sánchez, M Calderón; Cebra, D; Chakaberia, I; Chaloupka, P; Chan, BK; Chang, F-H; Chang, Z; Chankova-Bunzarova, N; Chatterjee, A; Chen, D; Chen, J; Chen, JH; Chen, X; Chen, Z; Cheng, J; Cherney, M; Chevalier, M; Choudhury, S; Christie, W; Chu, X; Crawford, HJ; Csanád, M; Daugherity, M; Dedovich, TG; Deppner, IM; Derevschikov, AA; Didenko, L; Dong, X; Drachenberg, JL; Dunlop, JC; Edmonds, T; Elsey, N; Engelage, J; Eppley, G; Esumi, S; Evdokimov, O; Ewigleben, A; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, CJ; Feng, Y; Filip, P; Finch, E; Fisyak, Y; Francisco, A; Fulek, L; Gagliardi, CA; Galatyuk, T; Geurts, F; Ghimire, N; Gibson, A; Gopal, K; Gou, X; Grosnick, D; Guryn, W; Hamad, AI; Hamed, A; Harabasz, S; Harris, JW; He, S; He, W; He, XH; He, Y; Heppelmann, S; Herrmann, N; Hoffman, E; Holub, L; Hong, Y
Source
Physical Review Letters. 126(16)
Subject
Language
Abstract
Global polarization of Ξ and Ω hyperons has been measured for the first time in Au+Au collisions at sqrt[s_{NN}]=200 GeV. The measurements of the Ξ^{-} and Ξ[over ¯]^{+} hyperon polarization have been performed by two independent methods, via analysis of the angular distribution of the daughter particles in the parity violating weak decay Ξ→Λ+π, as well as by measuring the polarization of the daughter Λ hyperon, polarized via polarization transfer from its parent. The polarization, obtained by combining the results from the two methods and averaged over Ξ^{-} and Ξ[over ¯]^{+}, is measured to be ⟨P_{Ξ}⟩=0.47±0.10(stat)±0.23(syst)% for the collision centrality 20%-80%. The ⟨P_{Ξ}⟩ is found to be slightly larger than the inclusive Λ polarization and in reasonable agreement with a multiphase transport model. The ⟨P_{Ξ}⟩ is found to follow the centrality dependence of the vorticity predicted in the model, increasing toward more peripheral collisions. The global polarization of Ω, ⟨P_{Ω}⟩=1.11±0.87(stat)±1.97(syst)% was obtained by measuring the polarization of daughter Λ in the decay Ω→Λ+K, assuming the polarization transfer factor C_{ΩΛ}=1.