Photoproduction of J/$ψ$ and dileptons in Pb-Pb collisions with nuclear overlap

Photon-photon reactions and the production of J/$\psi$ meson through photonuclear reactions have been extensively studied in ultra-peripheral heavy-ion collisions, in which the impact parameter is larger than twice the nuclear radius. In recent years, coherently photoproduced J/$\psi$ and dilepton production via photon-photon interactions have also been observed in nucleus-nucleus (A-A) collisions with nuclear overlap. The former can help to constrain the nuclear gluon distributions at low Bjorken-$x$ and high energy, while the latter could be used to further map the electromagnetic fields produced in heavy-ion collisions. In addition, these measurements can shed light on the theory behind photon-induced reactions in A-A collisions with nuclear overlap, including possible interactions of the measured probes with the formed and fast expanding quark-gluon plasma. Since the produced quarkonium is expected to keep the polarization of the incoming photon due to $s$-channel helicity conservation, the photoproduction origin of the J/$\psi$ yield excess at very low transverse momentum, $p_{\rm T}$, can be confirmed by the measurement of the J/$\psi$ polarization. The ALICE detector can perform quarkonium production measurements at both mid ($|y|<0.9$) and forward ($2.5