Benchmarking the non-flow contributions to the elliptic flow parameter (v 2) in proton-proton collisions

Abstract This manuscript reports on the elliptic flow parameter, v䃒, in proton-proton (p-p) collisions using PYTHIA8 event generator simulations. The typical Event Plane (EP) method v䃒 (EP) as the one used for the real data analysis has been adopted to measure the v䃒 of particles composed of different quark flavors, and produced at mid-pseudorapidity || 1 at center-of-mass energy s = 200 GeV and s = 13 TeV. The event plane has been constructed using the soft charged particles with transverse momentum (pₓ < 2 GeV/c) produced in various ranges. The pseudorapidity gap technique () between the particle of interest and the soft charged particles contributed to the event plane constructions has been utilized to benchmark the non-flow contributions. The v䃒^^{^, ^⁰}, v䃒^J/, , K, D, B, and the v䃒^₃₈ₑ show similar pattern dependence on the transverse momentum for the same, at both s = 200 GeV and s = 13 TeV. At each center-of-mass energy, the measured v䃒 shows obvious dependence on the quark flavor contents where v䃒^₃₈ₑ v䃒^J/, , K, D, B v䃒^^{^, ^⁰} for similar gap. The measured v䃒 shows slightly higher values at smaller s for particles of similar values of gaps, particularly at small gap. The measured v䃒 for all particles shows systematic decreases with increasing the gap as expected from the previous experimental results. Because PYTHIA8 simulations do not incorporate final state interactions, the v䃒 (EP) values reported here primarily reflect the non-flow contributions and its dependence on the quark contents, pseudorapidity gap as a function on pₓ at each center of mass-energy. These contributions should be carefully subtracted from the signal in real data analysis that employs the same event plane determination algorithm.