Flow Harmonics v_n in pPb and PbPb Collisions

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• 作者：Quan Wang
• 关键词：Flow ; Multiparticle Cumulant ; Event Plane ; Lee-Yang Zeros
• 刊名：Nuclear Physics A
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：956
• 期：Complete
• 页码：753-756
• 全文大小：196 K

文摘

Previous CMS measurements have demonstrated the collective nature of multiparticle correlations in high-multiplicity pPb collisions at the LHC. This collectivity is consistent with a hydrodynamic flow origin. However, it can also be interpreted in terms of initial state effects arising from gluon saturation. The pseudorapidity dependence of the azimuthal Fourier coefficients (v_n$v_n$) is expected to be sensitive to the underlying mechanism with, in the hydrodynamic picture, the longer lifetime of the fireball on the Pb-going side expected to lead to a larger flow signal than found on the p-going side. To investigate the detailed properties of the observed collectivity, differential v_n$v_n$ values in transverse momentum (p_T$p_{\mathrm{T}}$) and pseudorapidity (η  ) are presented over the full range of the CMS tracker detector (−2.4<η<2.4$-2.4<\eta <2.4$) for pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Results based on multiparticle analyses involving four or more particles are shown. An event plane analysis is presented where the influence of recently demonstrated event-plane decorrelation is considered. Comparisons are made with peripheral PbPb collisions measured at similar mid-rapidity particle multiplicities. The results will be discussed in the context of current models of the longitudinal dependence of the multiparticle correlations.