标题： 标量轻子模型中的喷注亚结构探针 via 顶夸克极化 显示英文标题

标题： Jet Substructure Probe on Scalar Leptoquark Models via Top Polarization

摘要： 轻子夸克及其与具有不同手性的费米子的耦合研究为区分不同的轻子夸克模型提供了一种有力工具。作为案例研究，我们重点关注两种特定的第三代标量轻子夸克模型，$S_3$和$R_2$，它们在电弱量子数以及与顶夸克耦合的手征结构上有所不同，从而导致不同的顶夸克极化状态。为了增强分析的有效性，我们采用了诸如Soft Drop、$N$-子团度、我们的自定义$b$标记方法以及其他事件变量等喷注亚结构技术。该分析使用了固定半径和动态半径喷注聚类算法。通过提升决策树（BDT）进行了多元分析，以从标准模型背景中分离信号。对于轻子夸克质量为1250 GeV的情况，在14 TeV高亮度大型强子对撞机（HL-LHC）上实现了高达$5.3\,\sigma$的信号显著性。此外，基于$CL_s$的轮廓似然估计器被应用于对极化敏感的变量，以区分这两种模型。 为了增强两种模型之间的区分度，通过训练一个BDT网络以区分$S_3$和$R_2$模型，获得了额外的BDT分类器评分。在选定的信号区域中，该BDT分类器评分提供了高达$3.2\,\sigma$的区分度分数，优于传统的变量$E_b/E_t$和$\cos\theta_b$等。 显示英文摘要

摘要： The study of leptoquarks and their couplings to fermions with different chiralities provides a powerful tool for distinguishing among different leptoquark models. As a case study, we focus on two specific third-generation scalar leptoquark models, $S_3$ and $R_2$, which differ in their electroweak quantum numbers and chiral structures of couplings to the top quark, leading to distinct top-quark polarization states. To enhance the efficacy of the analysis, we employ jet substructure techniques like Soft Drop, $N$-subjettiness, and our custom $b$-tagging method, along with other event variables. The analysis has been performed using both fixed radius and dynamic radius jet clustering algorithms. A multivariate analysis using a boosted decision tree (BDT) is performed to isolate signal from the Standard Model background. For a leptoquark mass of 1250 GeV, the analysis achieves a signal significance of up to $5.3\,\sigma$ at the 14 TeV HL-LHC. Furthermore, a $CL_s$-based profile likelihood estimator is applied to polarization-sensitive variables to discriminate between the two models. To enhance separation between the two models, an additional BDT classifier score is obtained by training a BDT network to distinguish between the $S_3$ and $R_2$ models. In the chosen signal region, the BDT classifier score provides a separation score of up to $3.2\,\sigma$, outperforming traditional variables such as $E_b/E_t$ and $\cos\theta_b$.