The 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, 1<pT<100 GeV/c. The analysis focuses on the pT>10 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.

Azimuthal anisotropy of charged particles with transverse momentum up to 100 GeV/c in PbPb collisions at √sNN=5.02 TeV

Meridiani, P.;Amapane, N.;Argiro, S.;Bellan, R.;Costa, M.;Covarelli, R.;Kiani, B.;Migliore, E.;Monaco, V.;Monteil, E.;Obertino, M. M.;Pacher, L.;Ravera, F.;Romero, A.;Sacchi, R.;Sola, V.;Solano, A.;
2018-01-01

Abstract

The 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.
2018
776
195
216
http://www.sciencedirect.com/science/journal/03702693
CMS; Flow; High-pT; Jet quenching; Parton energy loss; QGP; Nuclear and High Energy Physics
Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Fr...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1663875
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