Inclusive and differential cross section measurements of single top quark production in association with a Z boson in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
Inclusive and differential cross section measurements of single top quark production in association with a Z boson in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
复制标题
$$ sqrt{s} $$ = 13 TeV 质子-质子碰撞中与 Z 玻色子相关的单顶夸克产生的包容性和微分截面测量
DOI：
10.1007/jhep02(2022)107
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发表时间：
2022
影响因子：
5.4
通讯作者：
Jeitler, M.
中科院分区：
文献类型：
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作者：
Tumasyan, A.;Adam, W.;Andrejkovic, J. W.;Bergauer, T.;Chatterjee, S.;Damanakis, K.;Dragicevic, M.;Escalante Del Valle, A.;Frühwirth, R.;Jeitler, M.
与 Z 玻色子相关的单顶夸克产生的包容和微分截面是在质心能量为 13 TeV 的质子-质子碰撞中测量的，数据样本对应于 CMS 实验记录的 138 fb−1 的积分光度。根据与轻子 Z 玻色子和顶夸克衰变相关的三个轻子、电子或 μ 子的存在来选择事件。该测量产生了大于 30 GeV 的双轻子不变质量的包容性横截面 offb ，与标准模型 (SM) 计算一致，并且代表了迄今为止最精确的测定。与 Z 玻色子相关的顶夸克和顶反夸克产生的横截面之间的比率测量为：首次在部分子和粒子水平上进行差分测量。考虑几个运动学可观测量来研究过程的建模。将结果与对初始态 b 夸克来源的不同假设的理论预测进行比较，结果发现在不确定性范围内是一致的。此外，自旋不对称性对顶夸克偏振敏感，由部分子能级偏振角的微分分布确定为0. 54±0. 16（统计）±0。 06（系统），与SM预测一致。
Inclusive and differential cross sections of single top quark production in association with a Z boson are measured in proton-proton collisions at a center-of-mass energy of 13 TeV with a data sample corresponding to an integrated luminosity of 138 fb− 1 recorded by the CMS experiment. Events are selected based on the presence of three leptons, electrons or muons, associated with leptonic Z boson and top quark decays. The measurement yields an inclusive cross section offb for a dilepton invariant mass greater than 30 GeV, in agreement with standard model (SM) calculations and represents the most precise determination to date. The ratio between the cross sections for the top quark and the top antiquark production in association with a Z boson is measured as. Differential measurements at parton and particle levels are performed for the first time. Several kinematic observables are considered to study the modeling of the process. Results are compared to theoretical predictions with different assumptions on the source of the initial-state b quark and found to be in agreement, within the uncertainties. Additionally, the spin asymmetry, which is sensitive to the top quark polarization, is determined from the differential distribution of the polarization angle at parton level to be 0. 54±0. 16 (stat)±0. 06 (syst), in agreement with SM predictions.