ATLAS measurements of two-particle correlations are presented for s=5.02 and 13 TeV pp collisions and for sNN=5.02 TeV p+Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle ÎÏ, and pseudorapidity separation Îη, using charged particles detected within the pseudorapidity interval |η|<2.5. Azimuthal modulation in the long-range component of the correlation function, with |Îη|>2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2ÎÏ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3ÎÏ) and cos(4ÎÏ) modulation. The Fourier coefficients vn,n associated with the cos(nÎÏ) modulation of the correlation functions for n=2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(nÏ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2-4. The integrated luminosities used in this analysis are, 64 nb-1 for the s=13 TeV pp data, 170 nb-1 for the s=5.02 TeV pp data, and 28 nb-1 for the sNN=5.02 TeV p+Pb data.
Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for pp collisions at s =5.02 and 13 TeV and p+Pb collisions at sNN =5.02 TeV with the ATLAS detector
Amoroso, S.;Barbero, M.;Bellagamba, L.;Benitez, J.;Bona, M.;Cairo, V. M.;Callea, G.;Cao, T.;Capua, M.;Cardillo, F.;Carli, I.;Cavaliere, V.;Cerri, A.;Chen, H.;Chiarella, V.;Colombo, T.;Conti, G.;Crosetti, G.;David, C.;De Maria, A.;De Pedis, D.;Del Gaudio, M.;Fabbri, L.;Farina, C.;Fischer, A.;Francis, D.;Gabrielli, A.;Gabrielli, A.;Glasman, C.;Iacobucci, G.;Iodice, M.;Jackson, B.;La Rotonda, L.;Le, B.;Li, C.;Li, S.;Liu, J.;Liu, L.;Liu, M.;Liu, Y.;Lu, N.;Madaffari, D.;Mancini, G.;Martinez, M.;Mastroberardino, A.;Melo, M.;Meoni, E.;Merola, L.;Perini, L.;Petrucci, F.;Ragusa, F.;Rinaldi, L.;Scarfone, V.;Schioppa, M.;Sessa, M.;Silva, J.;Simon, D.;Spagnolo, S.;Sun, S.;Tassi, E.;Terron, J.;Terzo, S.;Veneziano, S.;Wang, J.;Wang, J.;Wang, R.;Wang, W.;Youssef, S.;Zhang, L.;Zhang, L.;Zhang, M.;Zhang, R.;Zhang, R.;Zhou, B.;Zhou, M.;Zhou, M.;Zhu, J.;
2017-01-01
Abstract
ATLAS measurements of two-particle correlations are presented for s=5.02 and 13 TeV pp collisions and for sNN=5.02 TeV p+Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle ÎÏ, and pseudorapidity separation Îη, using charged particles detected within the pseudorapidity interval |η|<2.5. Azimuthal modulation in the long-range component of the correlation function, with |Îη|>2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2ÎÏ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3ÎÏ) and cos(4ÎÏ) modulation. The Fourier coefficients vn,n associated with the cos(nÎÏ) modulation of the correlation functions for n=2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(nÏ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2-4. The integrated luminosities used in this analysis are, 64 nb-1 for the s=13 TeV pp data, 170 nb-1 for the s=5.02 TeV pp data, and 28 nb-1 for the sNN=5.02 TeV p+Pb data.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.