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arXiv 1812.01151hep-ph
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5个TeV p-Pb碰撞中识别强子$\bf p_t$谱的二分量模型

A two-component model for identified-hadron $\bf p_t$ spectra from 5 TeV p-Pb collisions

Thomas A. Trainor

摘要:

在相对论重离子对撞机(RHIC)的重离子计划准备阶段,$d$ -Au碰撞被指定为控制实验,以在更中心的Au-Au碰撞中发现夸克-胶子等离子体(QGP),两个系统的对比结果似乎支持了这一发现。与此相反,最近的结果($p_t$ -频谱和角相关功能)从$p$铅碰撞在大型强子对撞机(LHC)已被解释为支持要求的流体动力学流动和QGP形成,即使在小碰撞系统。本研究通过5 TeV $p$ -Pb碰撞的识别强子(PID)$p_t$谱的双组分(软+硬)模型(TCM)来解决这些问题。$p$ -Pb中心性采用来自同一系统的集合平均$\bar p_t$数据的既往研究。π介子、K介子、质子和λ介子的$p$ -Pb $p_t$谱由TCM在其点对点不确定度内描述。TCM硬组分与$p$ -Pb中心性的不变性表明,相对于$p$ - $p$碰撞,$p$ -Pb碰撞中的射流形成保持不变,并且径向流对光谱的贡献可以忽略不计。这些$p$ -Pb TCM结果对解释A-A碰撞中QGP形成的类似数据特征具有意义。

英文摘要:

In preparation for the heavy ion program at the relativistic heavy ion collider (RHIC) $d$-Au collisions were designated as a control experiment for possible discovery of a quark-gluon plasma (QGP) in more-central Au-Au collisions, and contrasting results from the two systems seemed to support such a discovery. In contrast, recent results ($p_t$-spectrum and angular-correlation features) from $p$-Pb collisions at the large hadron collider (LHC) have been interpreted to support claims of hydrodynamic flows and QGP formation even in small collision systems. The present study addresses such claims via a two-component (soft + hard) model (TCM) of identified-hadron (PID) $p_t$ spectra from 5 TeV $p$-Pb collisions. $p$-Pb centrality is adopted from a previous study of ensemble-mean $\bar p_t$ data from the same system. $p$-Pb $p_t$ spectra for pions, kaons, protons and Lambdas are described by the TCM within their point-to-point uncertainties. Invariance of the TCM hard component vs $p$-Pb centrality indicates that jet formation remains unchanged in $p$-Pb collisions relative to $p$-$p$ collisions, and radial-flow contributions to spectra are negligible. These $p$-Pb TCM results have implications for interpretation of similar data features from A-A collisions in terms of QGP formation.

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