AbstractTwo-particle transverse momentum correlation functions are a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $$G_{2}\left( \varDelta \eta ,\varDelta \varphi \right) $$
G
2
Δ
η
,
Δ
φ
is of particular interest for its potential sensitivity to the shear viscosity per unit of entropy density $$\eta /s$$
η
/
s
of the quark-gluon plasma formed in heavy-ion collisions. We use the UrQMD, AMPT, and EPOS models for Au–Au at $$\sqrt{s_\mathrm{NN}}$$
s
NN
= 200 GeV and Pb–Pb at $$\sqrt{s_\mathrm{NN}}$$
s
NN
= 2760 GeV to investigate the long range azimuthal dependence of $$G_{2}\left( \varDelta \eta ,\varDelta \varphi \right) $$
G
2
Δ
η
,
Δ
φ
, and explore its utility to constrain $$\eta /s$$
η
/
s
based on charged particle correlations. We find that the three models yield quantitatively distinct transverse momentum Fourier harmonics coefficients $$a^{p_\mathrm{T}}_{n}$$
a
n
p
T
. We also observe these coefficients exhibit a significant dependence on $$\eta /s$$
η
/
s
in the context of the AMPT model. These observations suggest that exhaustive measurements of the dependence of $$G_{2}\left( \varDelta \varphi \right) $$
G
2
Δ
φ
with collision energy, system size, collision centrality, in particular, offer the potential to distinguish between different theoretical models and their underlying assumptions. Exhaustive analyses of $$G_{2}\left( \varDelta \varphi \right) $$
G
2
Δ
φ
obtained in large and small systems should also be instrumental in establishing new constraints for precise extraction of $$\eta /s$$
η
/
s
.
Azimuthal dependence of two-particle transverse momentum current correlations
