Dilepton photoproduction measures the fluctuations of initial electromagnetic fields in nuclear collisions

Abstract

Dilepton production from two photon interactions $\gamma \gamma \to l^{+}{l}^{-}$ are studied in semi-central and peripheral nuclear collisions. Based on Weizsäcker-Williams approach, it is shown that the dilepton photoproduction is proportional to the electromagnetic (EM) fields $\sim E^2{B}^2$ and therefore sensitive to the magnitude and lifetime of initial EM fields which last only for a short time and are hard to be measured in experiments directly. We propose dilepton photoproduction as a probe for the nuclear charge fluctuations, which are crucial for the electric/magnetic field induced chiral and charge particle evolutions. We calculate the relative standard deviation of dilepton mass spectrum with event-by-event fluctuating nuclear charge distributions (and EM fields).

4 pages, 4 figures

References in corpus (15)

• The Physics of Ultraperipheral Collisions at the LHC
• 200 A GeV Au+Au collisions serve a nearly perfect quark-gluon liquid
• Multiplicity scaling in ideal and viscous hydrodynamics
• Electron-Positron Pair Production in Relativistic Heavy Ion Collisions
• Anomalous Chiral Transport in Heavy Ion Collisions from Anomalous-Viscous Fluid Dynamics
• Low-$p_T$ $e^{+}{e}^{-}$ pair production in Au$+$Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and U$+$U collisions at $\sqrt{s_{NN}}$ = 193 GeV at STAR
• Coherent lepton pair production in hadronic heavy ion collisions
• Two-photon production of dilepton pairs in peripheral heavy ion collisions
• Charmonium Coherent Photoproduction and Hadroproduction with Effects of Quark Gluon Plasma
• Double-slit experiment at fermi scale: coherent photoproduction in heavy-ion collisions
• Dilepton Radiation in Heavy-Ion Collisions at Small Transverse Momentum
• Coherent photo-produced J$/\psi$ and dielectron yields in isobaric collisions
• Charmonium production in ultra-peripheral heavy ion collisions with two-photon processes
• ${\eta }_Q$ meson photoproduction in ultrarelativistic heavy ion collisions
• Two-Photon Interactions with Nuclear Breakup in Relativistic Heavy Ion Collisions