Fakultät für Mathematik und Physik, Albert-Ludwigs-Universität, Freiburg, Germany.
Phys Rev Lett. 2013 Oct 11;111(15):152301. doi: 10.1103/PhysRevLett.111.152301. Epub 2013 Oct 9.
Measurements of the variation of inclusive jet suppression as a function of relative azimuthal angle, Δφ, with respect to the elliptic event plane provide insight into the path-length dependence of jet quenching. ATLAS has measured the Δφ dependence of jet yields in 0.14 nb(-1) of √(s(NN))=2.76 TeV Pb+Pb collisions at the LHC for jet transverse momenta p(T)>45 GeV in different collision centrality bins using an underlying event subtraction procedure that accounts for elliptic flow. The variation of the jet yield with Δφ was characterized by the parameter, v(2)(jet), and the ratio of out-of-plane (Δφπ/2) to in-plane (Δφ0) yields. Nonzero v(2)(jet) values were measured in all centrality bins for p(T)<160 GeV. The jet yields are observed to vary by as much as 20% between in-plane and out-of-plane directions.
测量包含喷注抑制的各向异性,作为相对于椭圆事件平面的相对方位角 Δφ 的函数,可以深入了解喷注淬灭的路径长度依赖性。ATLAS 已经在 LHC 上进行的 0.14 nb(-1) 的 √(s(NN))=2.76 TeV Pb+Pb 碰撞中,使用了一种底层事件减除方法,该方法考虑了椭圆流,测量了不同碰撞中心度 bin 中 p(T)>45 GeV 的喷注横动量的喷注产额的 Δφ 依赖性。喷注产额随 Δφ 的变化由参数 v(2)(jet)和离面(Δφπ/2)与面内(Δφ0)产额的比值来描述。在所有中心度 bin 中,都测量到了 p(T)<160 GeV 时非零的 v(2)(jet)值。在面内和离面方向之间,喷注产额的变化高达 20%。