论文标题
5.02 TEV P+PB碰撞的多重波动和相关性在零影响参数
Multiplicity fluctuations and correlations in 5.02 TeV p+Pb collisions at zero impact parameter
论文作者
论文摘要
我们提出了一种贝叶斯方法，可从最小偏置数据中重建逐件划分的事件多样性波动和零影响参数的速度相关性，而无需假设碰撞动力学模型。我们在使用Angantyr模型的蒙特卡洛模拟上对其进行了测试，然后将其应用于$ \ sqrt {s _ {\ rm nn}} = 5.02 $ tev的p+pb碰撞中带电的多重性和横向能量的分布数据。 $ b = 0 $碰撞中的波动是量子波动，主要来自质子波函数，因此有可能约束质子的亚核结构。发现Angantyr模型高估了波动。此外，我们发现，随着速度的增加（向PB-to-tone侧），不仅多样性密度增加，而且增加了其相对事件的划分波动。在具有Angantyr的模拟以及QCD偶极模型的模拟中也观察到了这种违反直觉现象，在该模型中，它的起源可以追溯到产生胶子的分支过程。
We present a Bayesian method to reconstruct event-by-event multiplicity fluctuations and rapidity correlations in p+Pb collisions at zero impact parameter from minimum-bias data, without assuming any model of the collision dynamics. We test it on Monte Carlo simulations with the Angantyr model, then apply it to ATLAS data on the distribution of charged multiplicity and transverse energy in p+Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV. Fluctuations in $b=0$ collisions are quantum fluctuations which originate mostly from the proton wave function, and therefore have the potential to constrain the subnucleonic structure of the proton. The Angantyr model is found to overestimate fluctuations. In addition, we find that as the rapidity increases (towards the Pb-going side), not only the multiplicity density increases, but also its relative event-by-event fluctuation. This counter-intuitive phenomenon is also observed in simulations with Angantyr, and with the QCD dipole model, where its origin can be traced back to the branching process through which gluons are produced.
