论文标题
评估Blast-Wave模型作为5 TEV P-PB $ \ BF P_T $ SPECTRA的描述
Evaluating the blast-wave model as a description of 5 TeV p-Pb $\bf p_t$ spectra
论文作者
论文摘要
爆炸波（BW）频谱模型被解释为在高能量A-B碰撞中相对于摩尔摩氏（CM）框架的强子发射系统的相对论运动（集体流）。从本质上讲，CM框架中的任何频谱偏差都远离参考分布（例如横向质量$ m_t $上的Boltzmann分布），以揭示流动的粒子源。爱丽丝合作将BW模型应用于从5个TEV $ p $ -PB碰撞的四个强子物种识别的强子（PID）光谱。从模型中拟合BW参数$ t_ {kin} $（冻结温度）和$ \langleβ_t\ rangle $（横向速度），这表明在更中心$ p $ -pb碰撞中强烈径向扩展。鉴于强大的径向扩展应由大密度梯度驱动，因此小$ P $ -PB碰撞系统的这种结果是违反直觉的。本研究旨在解决这个问题。采用了几种方法来评估BW模型数据描述的质量，包括对数衍生物和Z分数统计量。研究了BW模型定义在数据对数据的几个应用程序中的稳定性。 BW模型数据描述与以前已应用于相同$ p $ -PB PID光谱的两种组件（软+硬）模型（TCM）相比。一般的结论是，BW模型根据标准统计措施被$ P $ -PB PID频谱数据伪造，并且拟合的参数值无法传达预期的含义。 TCM提供的统计上可接受的数据描述表明，与常规QCD一致的其他碰撞机制（弹丸 - 核解离，dijet产生）更可能导致观察到的光谱特征。
The blast-wave (BW) spectrum model is interpreted to reveal relativistic motion (collective flow) of the hadron emission system relative to the center-of-momentum (CM) frame in high-energy A-B collisions. In essence, any spectrum deviation in the CM frame from a reference distribution (e.g. Boltzmann distribution on transverse mass $m_t$) is interpreted to reveal a flowing particle source. The ALICE collaboration has applied the BW model to identified hadron (PID) spectra for four hadron species from 5 TeV $p$-Pb collisions. From model fits BW parameters $T_{kin}$ (freeze-out temperature) and $\langle β_t \rangle$ (transverse speed) are inferred that suggest strong radial expansion in more-central $p$-Pb collisions. Such results from the small $p$-Pb collision system are counterintuitive given that strong radial expansion should be driven by large density gradients. The present study is intended to address that problem. Several methods are employed to evaluate the quality of the BW model data description, including logarithmic derivatives and the Z-score statistic. The stability of the BW model definition across several applications to data is investigated. The BW model data description is compare to that of the two-component (soft+hard) model (TCM) that has been previously applied to the same $p$-Pb PID spectra. The general conclusion is that the BW model is falsified by $p$-Pb PID spectrum data according to standard statistical measures and that the fitted parameter values do not convey the intended meaning. Statistically acceptable data descriptions provided by the TCM indicate that other collision mechanisms (projectile-nucleon dissociation, dijet production), that are consistent with conventional QCD, are more likely responsible for observed spectrum characteristics.
