论文标题
核碰撞中最初的状态动量各向异性的可观察签名
Observable signatures of initial state momentum anisotropies in nuclear collisions
论文作者
论文摘要
我们表明，在小型系统核冲突中，椭圆动量各向异性，$ v_2 $和平均横向动量$ [p_t] $之间的相关性带有有关观察到的动量各向异性的起源的信息。使用混合IP-Glasma+\ textsc {Music}+URQMD模型进行计算，其中包括最终状态响应对初始几何响应的贡献以及最初的状态动量的颜色玻璃冷凝物的各向异性，可以预测相关器$ \ hat privesity的特征符号变化（v_2^2，[p_p_t） $ \ sqrt {s} = 200 \，{\ rm gev} $和$ \ sqrt {s} = 5.02 \，{\ rm tev} $的p+pb碰撞。在没有初始状态动量各向异性的计算中没有这种标志变化。该模型进一步预测了$ \hatρ（v_2^2，[p_t]）$之间的定性差异，$ \ sqrt {s} = 200 \，{\ rm gev} $ {\ rm gev} $和pb+pb碰撞在$ \ sqrt $ {后者显示外围事件的标志变化。 O+O碰撞在不同碰撞能量时的预测显示出相似的行为。对小型和大型系统中$ \hatρ（v_2^2，[p_t]）$的这些独特的定性特征的实验性观察将构成有力的证据证明最初状态动量各向异性各向异性由颜色玻璃冷凝物有效理论预测。
We show that the correlation between the elliptic momentum anisotropy, $v_2$, and the average transverse momentum, $[p_T]$, at fixed multiplicity in small system nuclear collisions carries information on the origin of the observed momentum anisotropy. A calculation using a hybrid IP-Glasma+\textsc{Music}+UrQMD model that includes contributions from final state response to the initial geometry as well as initial state momentum anisotropies of the Color Glass Condensate, predicts a characteristic sign change of the correlator $\hatρ(v_2^2,[p_T])$ as a function of charged particle multiplicity in p+Au and d+Au collisions at $\sqrt{s}=200\,{\rm GeV}$, and p+Pb collisions at $\sqrt{s}=5.02\,{\rm TeV}$. This sign change is absent in calculations without initial state momentum anisotropies. The model further predicts a qualitative difference between the centrality dependence of $\hatρ(v_2^2,[p_T])$ in Au+Au collisions at $\sqrt{s}=200\,{\rm GeV}$ and Pb+Pb collisions at $\sqrt{s}=5.02\,{\rm TeV}$, with only the latter showing a sign change in peripheral events. Predictions for O+O collisions at different collision energy show a similar behavior. Experimental observation of these distinct qualitative features of $\hatρ(v_2^2,[p_T])$ in small and large systems would constitute strong evidence for the presence and importance of initial state momentum anisotropies predicted by the Color Glass Condensate effective theory.
