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Sirunyan A., Tumasyan A., Adam W., Asilar E., Bergauer T., Brandstetter J., ...More
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol.776, pp.195-216, 2018 (SCI-Expanded)
© 2017 The AuthorThe Fourier coefficients v2 and v3 characterizing the anisotropy of the azimuthal distribution of charged particles produced in PbPb collisions at sNN=5.02 TeV are measured with data collected by the CMS experiment. The measurements cover a broad transverse momentum range, 110 GeV/c range, where anisotropic azimuthal distributions should reflect the path-length dependence of parton energy loss in the created medium. Results are presented in several bins of PbPb collision centrality, spanning the 60% most central events. The v2 coefficient is measured with the scalar product and the multiparticle cumulant methods, which have different sensitivities to initial-state fluctuations. The values from both methods remain positive up to pT∼60–80 GeV/c, in all examined centrality classes. The v3 coefficient, only measured with the scalar product method, tends to zero for pT≳20 GeV/c. Comparisons between theoretical calculations and data provide new constraints on the path-length dependence of parton energy loss in heavy ion collisions and highlight the importance of the initial-state fluctuations.