Measuring neutron skin by grazing isobaric collisions

Neutron skin thickness ($\mathrm{\ensuremath{\Delta}}{r}_{\mathrm{np}}$) of nuclei and the inferred nuclear symmetry energy are critical importance to physics astrophysics. It is traditionally measured by processes with significant theoretical uncertainties. We recently proposed an indirect measurement $\mathrm{\ensuremath{\Delta}}{r}_{\mathrm{np}}$ charged hadron multiplicities in central isobaric collisions at relativistic energies, which sensitive densities. In this Letter, we propose a direct using net-charge ultraperipheral (grazing) those isobars, under assumption that they simple superimposition nucleon-nucleon interactions. illustrate novel approach trento urqmd models.