Measurements of two- and multi-particle angular correlations in pp collisions at √s = 5, 7, and 13 TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0 pb−1 (5 TeV), 6.2 pb−1 (7 TeV), and 0.7 pb−1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of K0 S and Λ/Λ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), K0 S, and Λ/Λ, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT ≈ 2 GeV/c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from twoparticle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed longrange correlations in high-multiplicity pp collisions.

Evidence for collectivity in pp collisions at the LHC / Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Asilar, E., Bergauer, T., Brandstetter, J., Brondolin, E., Dragicevic, M., Erö, J., Flechl, M., Friedl, M., Frühwirth, R., Ghete, V.M., Hartl, C., Hörmann, N., Hrubec, J., Jeitler, M., König, A., Krätschmer, I., et al.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 765:(2017), pp. 193-220. [10.1016/j.physletb.2016.12.009]

Evidence for collectivity in pp collisions at the LHC

MARZOCCHI, BADDER;BARONE, Luciano Maria;CIPRIANI, MARCO;D'IMPERIO, GIULIA;DEL RE, Daniele;GELLI, SIMONE;LONGO, Egidio;ORGANTINI, Giovanni;PARAMATTI, Riccardo;PREIATO, FEDERICO;RAHATLOU, SHAHRAM;SANTANASTASIO, FRANCESCO;
2017

Abstract

Measurements of two- and multi-particle angular correlations in pp collisions at √s = 5, 7, and 13 TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0 pb−1 (5 TeV), 6.2 pb−1 (7 TeV), and 0.7 pb−1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of K0 S and Λ/Λ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), K0 S, and Λ/Λ, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT ≈ 2 GeV/c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from twoparticle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed longrange correlations in high-multiplicity pp collisions.
2017
CMS; correlation; heavy ion; physics; pp; ridge; Nuclear and High Energy Physics
01 Pubblicazione su rivista::01a Articolo in rivista
Evidence for collectivity in pp collisions at the LHC / Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Asilar, E., Bergauer, T., Brandstetter, J., Brondolin, E., Dragicevic, M., Erö, J., Flechl, M., Friedl, M., Frühwirth, R., Ghete, V.M., Hartl, C., Hörmann, N., Hrubec, J., Jeitler, M., König, A., Krätschmer, I., et al.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 765:(2017), pp. 193-220. [10.1016/j.physletb.2016.12.009]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/982266
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