Global polarization measurement in Au plus Au collisions

作者：Abelev B I^*; Aggarwal M M; Ahammed Z; Anderson B D; Arkhipkin D; Averichev G S; Bai Y; Balewski J; Barannikova O; Barnby L S; Baudot J; Baumgart S; Belaga V V; Bellingeri Laurikainen A; Bellwied R; Benedosso F; Betts R R; Bhardwaj S; Bhasin A; Bhati A K; Bichsel H; Bielcik J; Bielcikova J; Bland L C; Blyth S L; Bombara M; Bonner B E; Botje M; Bouchet J; Brandin A V; Burton T P; Bystersky M; Cai X Z; Caines H

来源：Physical Review C, 2007, 76(2): 024915.

DOI：10.1103/PhysRevC.76.024915

The system created in noncentral relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Because of spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Lambda and (Lambda) over bar hyperon global polarization measurements in Au+Au collisions at root s(NN)=62.4 and 200 GeV performed with the STAR detector at the BNL Relativistic Heavy Ion Collider (RHIC). The observed global polarization of Lambda and (Lambda) over bar hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |P-Lambda,P-(Lambda) over bar|<= 0.02, is compared with the theoretical values discussed recently in the literature.

• 出版日期2007-8
• 单位华中师范大学; 中国科学院上海应用物理研究所; 中国科学技术大学; 清华大学