Electromagnetic interaction of low transverse momentum charged leptons with heavy nuclei in ultra-peripheral ultra-relativistic heavy-ion collisions

Abstract

The photon–photon interaction in ultra-relativistic heavy-ion collision is a source of the charged lepton pairs. The photon-photon fusion leads to the lepton creation in broad configuration space around the “collision” point. Those created close to heavy nuclei may undergo strong electromagnetic interaction with them. The impact parameter space distributions of electrons/positrons and charged muons are calculated within the b-space EPA model of such collisions. The evolution of $$e^+/e^-$$ e + / e - and $$\mu ^+/\mu ^-$$ μ + / μ - distributions due to the electromagnetic interaction of leptons with nuclei is studied, and the distortion of rapidity and transverse momentum distributions are shown. A part of the analysis is independent of the production model. We show the first exploratory results for the reaction Pb + Pb at $$\sqrt{s_{NN}} = $$ s NN = 17.3 GeV (SPS) and 200 GeV (RHIC) energies. We provide results for selected creation points and when integrating over their positions as dictated by the b-space EPA model. We observe sizeable effects for $$e^+ / e^-$$ e + / e - and much smaller effects for $$\mu ^+ / \mu ^-$$ μ + / μ - . We predict a possible sizeable accumulation of leptons with rapidities close to the beam rapidity. The EM effects lead to asymmetry in the production of $$e^+$$ e + and $$e^-$$ e - or $$\mu ^+$$ μ + and $$\mu ^-$$ μ - .

Exciting Ions: a Systematic Treatment of Ultraperipheral Heavy Ion Collisions with Nuclear Breakup

“…Theoretical calculations that do account for this effect [33] on the other hand describe the trend of the CMS data (see e.g. [34][35][36][37][38] for other studies), but without providing a full MC treatment. In this paper, we therefore extend the SuperChic MC generator to account for mutual ion dissociation, including its full process and kinematic dependence, as well as the interplay with the survival factor probability.…”

Born-Infeld Nonlinear Electromagnetism in Relativistic Heavy Ion Collisions

“…In recent years, relativistic heavy ion collisions have been explored as a testing ground for strong electromagnetic (EM) field effects [1][2][3][4][5][6]. In peripheral collisions with large impact parameters, electromagnetic forces dominate the scattering processes, and strong field effects such as light-light scattering and spontaneous pair production can be observed.…”