"Figure 2 ($IP_\mathrm{2D}$)" of "Search for new particles decaying to a jet and an emerging jet"

Distributions of $\langle IP_{\mathrm{2D}}\rangle$ for background (black) and for signals with a mediator mass of 1 TeV and a dark pion proper decay length of 25 mm, for various dark pion masses.

针对不同暗π介子（dark pion）质量，分别给出本底（黑色曲线）以及传递子（mediator）质量为1太电子伏特、暗π介子固有衰变长度为25毫米的信号样本的平均二维冲击参数（⟨IP₂D⟩）分布。