A large anti-correlation signal between elliptic flow $v_2$ and average transverse momentum $[p_{\mathrm{T}}]$ was recently measured in small collision systems, consistent with a final-state hydrodynamic response to the initial geometry. This negative $v_2$–$[p_{\mathrm{T}}]$ correlation was predicted to change to positive correlation for events with very small charged particle multiplicity $N_{\mathrm{ch}}$ due to initial-state momentum anisotropies of the gluon saturation effects. However, the role of non-flow correlations is expected to be important in these systems, which is not yet studied. We estimate the non-flow effects in pp, pPb and peripheral PbPb collisions using Pythia and Hijing models, and compare them with the experimental data. We show that the non-flow effects are largely suppressed using the rapidity-separated subevent cumulant method (details of the cumulant framework are also provided). The magnitude of the residual non-flow is much less than the experimental observation in the higher $N_{\mathrm{ch}}$ region, supporting the final-state response interpretation. In the very low $N_{\mathrm{ch}}$ region, however, the sign and magnitude of the residual non-flow depend on the model details. Therefore, it is unclear at this moment whether the sign change of $v_2$–$[p_{\mathrm{T}}]$ can serve as evidence for initial state momentum anisotropies predicted by the gluon saturation.

椭圆流之间的大反相关信号 $v_2$ 和平均横向动量 $[{磷}_{\mathrm{吨}}]$最近在小型碰撞系统中进行了测量，与对初始几何形状的最终状态流体动力学响应一致。这种负$v_2$——$[{磷}_{\mathrm{吨}}]$ 对于具有非常小的带电粒子多样性的事件，相关性被预测为正相关性 $N_{\mathrm{ch}}$由于胶子饱和效应的初始状态动量各向异性。然而，非流动相关性的作用预计在这些系统中很重要，但尚未研究。我们使用Pythia和Hijing模型估计pp、p Pb 和外围 PbPb 碰撞中的非流动效应，并将它们与实验数据进行比较。我们表明，使用快速分离的子事件累积量方法（还提供了累积量框架的详细信息）在很大程度上抑制了非流动效应。残余不流动的幅度远小于实验观察到的较高$N_{\mathrm{ch}}$区域，支持最终状态响应解释。在极低$N_{\mathrm{ch}}$然而，残差非流动的符号和大小取决于模型细节。因此，目前尚不清楚 的符号是否发生变化$v_2$——$[{磷}_{\mathrm{吨}}]$ 可以作为由胶子饱和度预测的初始状态动量各向异性的证据。