"Figure 3 (right)" of "Measurement of the production cross section for Z + b jets in proton-proton collisions at $\sqrt{s}$ = 13 TeV"

The measurements of the cross section of the \PZ boson, decaying to dielectrons or dimuons, in association with at least one bottom quark jet are performed with proton-proton collision data at $\sqrt{s}=$ 13\TeV. The data sample corresponds to an integrated luminosity of 137.1\fbinv, collected by the CMS experiment at the LHC. The integrated cross sections of \PZ~$+\geq$~1~\cPqb~jet\xspace and \PZ~$+\geq$~2~\cPqb~jets\xspace are reported for the electron, muon, and combined channels with full Run 2 data. The measured integrated cross sections are 6.52 $\pm$ 0.04 (stat) $\pm$ 0.40 (syst) $\pm$ 0.14 (theo) pb for \PZ~$+\geq$~1~\cPqb~jet\xspace and 0.65 $\pm$ 0.03 (stat) $\pm$ 0.07 (syst) $\pm$ 0.02 (theo) pb for \PZ~$+\geq$~2~\cPqb~jets\xspace. The differential cross section distributions are measured as a function of various kinematic observables that are useful for precision tests of the perturbative quantum chromodynamics predictions. The ratios of integrated and differential cross sections of \PZ~$+\geq$~2~\cPqb~jets\xspace and \PZ~$+\geq$~1~\cPqb~jet\xspace processes are also determined. The value of the integrated cross section ratio measured in the combined channel is 0.100 $\pm$ 0.005 (stat) $\pm$ 0.007 (syst) $\pm$ 0.003 (theo). All of the measurements are compared with predictions from Monte Carlo simulations.本研究利用大型强子对撞机（LHC）上紧凑型缪子线圈（CMS）实验采集的质心系能量√s=13 TeV的质子-质子碰撞数据，对伴随至少一个底夸克喷注（bottom quark jet）且衰变至双电子或双缪子的Z玻色子（Z boson）的截面开展了测量。本次分析使用的数据样本对应的积分亮度（integrated luminosity）为137.1 fb⁻¹。本文报道了电子道、缪子道及联合道下，结合LHC Run 2全运行数据的Z玻色子伴随≥1个底夸克喷注以及Z玻色子伴随≥2个底夸克喷注的积分截面。其中，Z玻色子伴随≥1个底夸克喷注过程的积分截面测量结果为6.52 ± 0.04（统计不确定性） ± 0.40（系统不确定性） ± 0.14（理论不确定性） pb；Z玻色子伴随≥2个底夸克喷注过程的积分截面测量结果为0.65 ± 0.03（统计不确定性） ± 0.07（系统不确定性） ± 0.02（理论不确定性） pb。研究还针对多种运动学可观测量测量了微分截面分布，该分布可用于微扰量子色动力学（perturbative quantum chromodynamics）预言的高精度检验。此外，本文还测定了Z玻色子伴随≥2个底夸克喷注与Z玻色子伴随≥1个底夸克喷注过程的积分截面比值与微分截面比值。在联合道中测得的积分截面比值为0.100 ± 0.005（统计不确定性） ± 0.007（系统不确定性） ± 0.003（理论不确定性）。所有测量结果均与蒙特卡洛（Monte Carlo）模拟预言进行了对比。