Momentum Anisotropy of Leptons from Two Photon Processes in Heavy Ion Collisions

Abstract

We investigate the azimuthal angular correlation between the lepton transverse momentum $P_{\perp }$ and the impact parameter $b_{\perp }$ in non-central heavy-ion collisions, where the leptons are produced through two-photon scattering. Among the Fourier harmonic coefficients, a significant $v_4$ asymmetry is found for the typical kinematics at RHIC and LHC with a mild dependence on the $P_{\perp }$, whereas $v_2$ is power suppressed by the lepton mass over $P_{\perp }$. This unique prediction, if confirmed from the experiments, shall provide crucial information on the production mechanism for the dilepton in two-photon processes.

Comments: updated to match the published version, title changed, 6 pages, 3 figures