Azimuthal anisotropy of charged particles with transverse momentum up to 100 GeV in PbPb collisions at sqrt(s[NN]) = 5.02 TeV

A.M. Sirunyan , M. Besançon (1) , F. Couderc (1) , M. Dejardin (1) , D. Denegri (1) , B. Fabbro (1) , J.L. Faure (1) , C. Favaro (1) , F. Ferri (1) , S. Ganjour (1) , S. Ghosh (1) , A. Givernaud (1) , P. Gras (1) , G. Hamel De Monchenault (1) , P. Jarry (1) , I. Kucher (1) , E. Locci (1) , M. Machet (1) , J. Malcles (1) , J. Rander (1) , A. Rosowsky (1) , M. Titov (1) , A. Abdulsalam (2) , I. Antropov (2) , S. Baffioni (2) , F. Beaudette (2) , P. Busson (2) , L. Cadamuro (2) , E. Chapon (2) , C. Charlot (2) , O. Davignon (2) , R. Granier De Cassagnac (2) , M. Jo (2) , S. Lisniak (2) , P. Mine (2) , M. Nguyen (2) , C. Ochando (2) , G. Ortona (2) , P. Paganini (2) , P. Pigard (2) , S. Regnard (2) , R. Salerno (2) , Y. Sirois (2) , A.G. Stahl Leiton (2) , T. Strebler (2) , Y. Yilmaz (2) , A. Zabi (2) , A. Zghiche (1) , J.-L. Agram (3) , J. Andrea (3) , A. Aubin (3) , D. Bloch (3) , J.-M. Brom (3) , M. Buttignol (3) , E.C. Chabert (3) , N. Chanon (3) , C. Collard (3) , E. Conte (3) , X. Coubez (3) , J.-C. Fontaine (3) , D. Gele (3) , U. Goerlach (3) , A.-C. Le Bihan (3) , P. Van Hove (3) , S. Gadrat (4) , S. Beauceron (5) , C. Bernet (5) , G. Boudoul (5) , C.A. Carrillo Montoya (5) , R. Chierici (5) , D. Contardo (5) , B. Courbon (5) , P. Depasse (5) , H. El Mamouni (5) , J. Fay (5) , S. Gascon (5) , M. Gouzevitch (5) , G. Grenier (5) , B. Ille (5) , Fabienne Lagarde (5) , I.B. Laktineh (5) , M. Lethuillier (5) , L. Mirabito (5) , A.L. Pequegnot (5) , S. Perries (5) , A. Popov , D. Sabes (5) , V. Sordini (5) , M. Vander Donckt (5) , P. Verdier (5) , S. Viret (5)

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 LLR - Laboratoire Leprince-Ringuet
3 DRS-IPHC - Département Recherches Subatomiques
4 CC-IN2P3 - Centre de Calcul de l'IN2P3
5 IPNL - Institut de Physique Nucléaire de Lyon

The Fourier coefficients v[2] and v[3] characterizing the anisotropy of the azimuthal distribution of charged particles produced in PbPb collisions at sqrt(s[NN])= 5.02 TeV are measured with data collected by the CMS experiment. The measurements cover a broad transverse momentum range, pt= 1-100 GeV. The analysis focuses on pt > 10 GeV 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 60x% most central events. The v[2] coefficient is measured with the scalar product and the multiparticle cumulant methods, which have different sensitivities to the initial-state fluctuations. The values of both methods remain positive up to pt ~ 70 GeV, in all examined centrality classes. The v[3] coefficient, only measured with the scalar product method, tends to zero for pt >~ 20 GeV. 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.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

A.M. Sirunyan, M. Besançon, F. Couderc, M. Dejardin, D. Denegri, et al.. Azimuthal anisotropy of charged particles with transverse momentum up to 100 GeV in PbPb collisions at sqrt(s[NN]) = 5.02 TeV. Physics Letters B, 2017, 776, pp.195. ⟨10.1016/j.physletb.2017.11.041⟩. ⟨in2p3-01454724⟩