Principle Component Analysis of two-particle correlations in PbPb and pPb collisions at CMS

详细信息    查看全文

• 作者：Jovan Milosevic ^{Jovan.Milosevic@cern.ch" class="auth_mail" title="E-mail the corresponding author} ; on behalf of the CMS collaboration
• 关键词：relativistic collisions ; collective flow
• 刊名：Nuclear Physics A
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：956
• 期：Complete
• 页码：308-311
• 全文大小：177 K

文摘

A Principle Component Analysis (PCA) of two-particle azimuthal correlations as a function of transverse momentum (p_T) is presented in PbPb collisions at 2.76 TeV and high-multiplicity pPb collisions at 5.02 TeV. The data were recorded using the CMS detector at the LHC. It was shown that factorization breaking of two-particle azimuthal correlations can be attributed to the effect of initial-state fluctuations. Using a PCA approach, Fourier coefficients of observed two-particle azimuthal correlations as a function of both particles' p_T are characterized into leading and sub-leading mode terms. The leading modes are essentially equivalent to anisotropy harmonics (v_n) previously extracted from two-particle correlation methods as a function of p_T. The sub-leading modes represent the largest sources of factorization breaking. In the context of hydrodynamic models, they are a direct consequence of initial-state fluctuations. The results are presented over a wide range of centrality and event multiplicity. The results are connected to the measurement of p_T-dependent flow factorization breaking.