Multiplicity and transverse momentum dependence of two- and four-particle correlations in pPb and PbPb collisions

作者：Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Eroe, J.; Fabjan, C.; Friedl, M.; Fruehwirth, R.; Ghete, V. M.; Hoermann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knuenz, V.; Krammer, M.; Kraetschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schoefbeck, R.; Strauss, J.; Taurok, A.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C. -E.; Mossolov, V.; Shumeiko, N.; Gonzalez, J. Suarez

来源：Physics Letters B, 2013, 724(4-5): 213-240.

DOI：10.1016/j.physletb.2013.06.028

• CMS
• Physics
• Heavy ions

Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 31 nb(-1), were collected during the 2013 LHC pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. The results are compared to 2.76 TeV semi-peripheral PbPb collision data, collected during the 2011 PbPb run, covering a similar range of particle multiplicities. The observed correlations are characterized by the near-side (vertical bar Delta phi vertical bar approximate to 0) associated pair yields and the azimuthal anisotropy Fourier harmonics (nu(n)). The second-order (nu(2)) and third-order (v(3)) anisotropy harmonics are extracted using the two-particle azimuthal correlation technique. A four-particle correlation method is also applied to obtain the value of nu(2) and further explore the multi-particle nature of the correlations. Both associated pair yields and anisotropy harmonics are studied as a function of particle multiplicity and transverse momentum. The associated pair yields, the four-particle nu(2), and the nu(3) become apparent at about the same multiplicity. A remarkable similarity in the nu(3) signal as a function of multiplicity is observed between the pPb and PbPb systems. Predictions based on the color glass condensate and hydrodynamic models are compared to the experimental results.

• 出版日期2013-7-23
• 单位中国地震局; 西北大学; 东北大学; 中央民族大学; 北京大学