  We investigate the $P_T$-broadening effects in dilepton production through
photon-photon scattering in heavy ion collisions. The QED multiple interaction
effects with the medium is found to be consistent with a recent observation of
low transverse momentum lepton pair from ATLAS collaboration at the LHC. We
further comment on the magnetic effects and point out a number of ways to
disentangle these two mechanisms. In particular, the rapidity dependence of the
$P_T$-broadening effects provide a unique probe to the magnetic effects.
