Arsene I, Bearden I G, Beavis D, Bekele S, Besliu C, Budick B, Bøggild H, Chasman C, Dalsgaard H H, Debbe R, Fox B, Gaardhøje J J, Hagel K, Jipa A, Johnson E B, Karabowicz R, Katryńska N, Kim E J, Larsen T M, Lee J H, Løvhøiden G, Majka Z, Murray M, Nygaard C, Natowitz J, Nielsen B S, Pal D, Qviler A, Ristea C, Röhrich D, Sanders S J, Staszel P, Tveter T S, Videbaek F, Yang H, Wada R
Department of Physics, University of Oslo, Oslo, Norway.
Phys Rev Lett. 2008 Jul 25;101(4):042001. doi: 10.1103/PhysRevLett.101.042001. Epub 2008 Jul 22.
The first measurements of xF-dependent single-spin asymmetries of identified charged hadrons, pi+/-, K+/-, and protons, from transversely polarized proton-proton collisions at 62.4 GeV at RHIC are presented. Large asymmetries are seen in the pion and kaon channels. The asymmetries in inclusive pi+ production, AN(pi+), increase with xF from 0 to approximately 0.25 and AN(pi-) decrease from 0 to approximately -0.4. Observed asymmetries for K- unexpectedly show positive values similar to those for K+, increasing with xF, whereas proton asymmetries are consistent with zero over the measured kinematic range. Comparisons of the data with predictions of QCD-based models are presented.
本文展示了在相对论重离子对撞机（RHIC）上，对62.4 GeV横向极化质子-质子碰撞中，已识别带电强子（π⁺/⁻、K⁺/⁻和质子）的x_F依赖单自旋不对称性的首次测量结果。在π介子和K介子通道中观察到了大的不对称性。在包容性π⁺产生中的不对称性AN(π⁺)，随着x_F从0增加到约0.25，而AN(π⁻)从0减小到约-0.4。K⁻的观测不对称性意外地显示出与K⁺相似的正值，并随x_F增加，而质子不对称性在测量的运动学范围内与零一致。还给出了数据与基于量子色动力学（QCD）模型预测的比较。
