Exploring Origins for Correlations between Flow Harmonics and Transverse Momentum in Small Collision Systems (Unambiguous Ambiguity)

Abstract

High statistics data sets from experiments at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) with small and large collision species have enabled a wealth of new flow measurements, including the event-by-event correlation between observables. One exciting such observable $\rho (v_n^2,[p_T])$ gauges the correlation between the mean transverse momentum of particles in an event and the various flow coefficients ($v_n$) in the same event [1]. Recently it has been proposed that very low multiplicity events may be sensitive to initial-state glasma correlations [2] rather than flow-related dynamics. We find utilizing the IP-JAZMA framework that the color domain explanation for the glasma results are incomplete. We then explore predictions from PYTHIA-8, and the version for including nuclear collisions called PYTHIA-ANGANTYR, which have only non-flow correlations and the AMPT model which has both non-flow and flow-type correlations. We find that PYTHIA-ANGANTYR has non-flow contributions to $\rho (v_n^2,[p_T])$ in p+O, p+Pb, O+O collisions that are positive at low multiplicity and comparable to the glasma correlations. It is striking that in PYTHIA-8 in p+p collisions there is actually a sign-change from positive to negative $\rho (v_n^2,[p_T])$ as a function of multiplicity. The AMPT results match the experimental data general trends in Pb+Pb collisions at the LHC, except at low multiplicity where AMPT has the opposite sign. In p+Pb collisions, AMPT has the opposite sign from experimental data and we explore this within the context of parton geometry. Predictions for p+O, O+O, and Xe+Xe are also presented.

15 pages, 17 figures, submitted for publication

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Cited by in corpus (9)

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• Impact of nuclear deformation on collective flow observables in relativistic U+U collisions
• Influence of nuclear structure in relativistic heavy-ion collisions
• Model investigations of the correlation between the mean transverse momentum and anisotropic flow in shape-engineered events
• Effect of nuclear structure on particle production in relativistic heavy-ion collisions using the AMPT model
• Model study of the energy dependence of the correlation between anisotropic flow and the mean transverse momentum in Au+Au collisions
• Large-rapidity ridge correlations from Color Glass Condensate
• Beam-energy dependence of correlations between mean transverse momentum and anisotropic flow of charged particles in Au+Au collisions at RHIC
• CGC-induced longitudinal ridge in p-Pb collisions