发表机构
Wayne State University（韦恩州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文利用PYTHIA模拟RHIC能量下pp碰撞，研究非流贡献的多重数依赖性，发现其不呈简单标度，挑战了LHC标准扣除方法在低能下的适用性。
AI 中文摘要
在高多重数pA和pp碰撞中观测到的近侧长程关联增强现象（通常称为脊）激发了量化小系统中可能集体效应的大量努力。在LHC小系统中，双粒子关联测量中非流贡献的估计通常依赖于喷注诱导的非流关联与事件多重性无关的假设。因此，该假设允许直接利用低多重数事件来估计和考虑高多重数非流贡献。本文利用PYTHIA事件生成器，在RHIC能量$\u221as = 200$ GeV的pp碰撞中，通过双粒子关联函数估计的非流贡献的多重数依赖性来研究该假设的有效性。观察到选择任何特定多重数范围本质上会引入喷注产生动力学的偏差。这些偏差在RHIC能量下引入了非流贡献的非平凡多重数依赖性。利用多种常用多重数估计器（包括中心快度带电粒子多重数、前向多重数和底层事件活动）研究了喷注碎裂和$p_{\ ext{T}}$微分截面随事件多重数的依赖性。结果表明，非流贡献不表现出简单的多重数标度，并对在LHC能量下使用的标准扣除程序在较低RHIC碰撞能量下的适用性提出了挑战。
英文摘要
The observation of a near-side enhancement in long-range correlations within high-multiplicity pA and pp collisions, commonly referred to as the ridge, has motivated significant efforts to quantify possible collective effects in small systems. Estimation of non-flow contributions in two-particle correlation measurements in small systems at the LHC typically relies on the assumption that jet-induced non-flow correlations are independent of event multiplicity. Consequently, this assumption allows the high-multiplicity non-flow to be estimated and accounted for by directly using low-multiplicity events. In this paper, the validity of this assumption is studied examining the multiplicity dependence of non-flow contributions estimated via two-particle correlation functions in pp collisions at RHIC energies $\sqrt{s} = 200$~GeV using the PYTHIA event generator. It is observed that selecting any specific multiplicity range inherently biases jet production dynamics. These biases introduce a non-trivial multiplicity dependence of the non-flow contribution at RHIC energies. The dependence of jet fragmentation and $p_{\text{T}}$-differential cross sections on event multiplicity is studied using a variety of commonly used multiplicity estimators, including mid-rapidity charged-particle multiplicity, forward multiplicity, and underlying-event activity. The results indicate that non-flow contributions do not exhibit simple multiplicity scaling and challenge the applicability of standard subtraction procedures utilized at LHC energies at lower RHIC collision energies.
Comments13 pages, 19 figures
