标题： 带电粒子产率在横向事件活动分类器$S_{T}$下的研究，$-$p 碰撞中的情况 显示英文标题

标题： Study of identified particle production as a function of transverse event activity classifier, $S_{T}$ in p$-$p collisions

摘要： 一种新的可观测量，$S_{T}$，在LHC能量下，通过质子-质子（p$-$p）碰撞中产生的带电粒子（$\sum_{i} p_{T_{i}}$）的横向动量之和来引入，以研究底层事件（UE）。底层事件（UE）被定义为质子-质子碰撞中不归因于主要硬散射过程，而是归因于质子其余部分伴随相互作用的部分。研究底层事件的传统方法通常是相对于事件中的主要粒子定义拓扑区域。横向区域通常对UE敏感，已使用各种分类器来区分UE活动区域的程度。 被识别粒子如 $\pi^{\pm}$， $K^{\pm}$， p ， $K_{S}^{0}$和 $\Lambda^{0}$在 p$-$p 碰撞中不同横向活动分类器范围内的 $\sqrt{s} = 13 $ TeV 使用 pQCD 启发的 PYTHIA 8 事件生成器进行研究。 对识别的粒子谱、平均多重性和平均横向动量进行了比较分析，相对于$S_{T}$，通过将结果与先前定义的$R_{T}$量进行比较来评估这种新观测量的性能。 显示英文摘要

摘要： A new observable, $S_{T}$, is introduced in terms of the sum of the transverse momentum of charged particles ($\sum_{i} p_{T_{i}}$ ) produced in proton proton (p$-$p) collisions at LHC energies to probe the underlying events (UE). The UE are defined as those aspects of proton-proton collisions that are not attributed to the primary hard scattering process, but rather to the accompanying interactions of the rest of the proton. The conventional approach of studying underlying events is usually carried out by defining topological regions with respect to the leading particle in an event. The transverse region is generally sensitive to UE and various classifiers have been used to discriminate the extent of UE activity regions. The production of identified particles like $\pi^{\pm}$, $K^{\pm}$, p , $K_{S}^{0}$, and $\Lambda^{0}$ are studied in different ranges of transverse activity classifier in p$-$p collisions at $\sqrt{s} = 13 $ TeV using pQCD inspired PYTHIA 8 event generator. A comparative analysis of the identified particle spectra, mean multiplicity and mean transverse momentum has been carried out with respect to $S_{T}$ and the performance of this new observable is gauged by comparing the results with previously defined $R_{T}$ observable.