Measurements of Multiparticle Correlations in d + Au Collisions at 200, 62.4, 39, and 19.6 GeV and p + Au Collisions at 200 GeV and Implications for Collective Behavior

Aidala, C.
Apadula, Nicole
Hill, John
Hotvedt, Nels
Lajoie, John
Lebedev, Alexandre
Lee, S. H.
Ogilvie, Craig
Patel, Milap
Perry, Joshua
Rinn, Timothy
Rosati, Marzia
Runchey, Jonathan
Sen, Abhisek
Shimomura, M.
Timilsina, Arbin
et al.
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Recently, multiparticle-correlation measurements of relativistic p/d(3)He + Au, p + Pb, and even p + p collisions show surprising collective signatures. Here, we present beam-energy-scan measurements of two, four-, and six-particle angular correlations in d + Au collisions at root s(NN) = 200, 62.4, 39, and 19.6 GeV. We also present measurements of two-and four-particle angular correlations in p + Au collisions at root s(NN) = 200 GeV. We find the four-particle cumulant to be real valued for d + Au collisions at all four energies. We also find that the four-particle cumulant in p + Au has the opposite sign as that in d + Au. Further, we find that the six-particle cumulant agrees with the four-particle cumulant in d + Au collisions at 200 GeV, indicating that nonflow effects are subdominant. These observations provide strong evidence that the correlations originate from the initial geometric configuration, which is then translated into the momentum distribution for all particles, commonly referred to as collectivity.


This article is published as Aidala, C., Y. Akiba, M. Alfred, V. Andrieux, K. Aoki, N. Apadula, H. Asano et al. "Measurements of multiparticle correlations in d+ Au collisions at 200, 62.4, 39, and 19.6 GeV and p+ Au collisions at 200 GeV and implications for collective behavior." Physical Review Letters 120, no. 6 (2018): 062302. DOI: 10.1103/PhysRevLett.120.062302. Posted with permission.