Coulomb nuclear interference effect in dipion production in ultraperipheral heavy ion collisions

Abstract

We study exclusive π + π − pair production near ρ 0 resonance peak in ultraperipheral heavy ion collisions. Pion pair can either be produced via two photon fusion process or from the decay of ρ 0 in photon-nuclear reaction. At very low pair transverse momentum, the electromagnetic and nuclear amplitudes become comparable. We show that the Coulomb nuclear interference amplitude gives rise to sizable cos φ and cos 3φ azimuthal asymmetries, which can be used to constrain the phase of the dipole-nucleus scattering amplitude.

Exploring gluon tomography with polarization dependent diffractive J/$ψ$ production

“…Moreover, sizable cos φ and cos 3φ azimuthal asymmetries that result from the Coulomb nuclear interference effect have been predicated in Ref. [64]. All in all, the linear polarization of coherent photons has been proven to be a powerful experimental tool for exploring novel QCD phenomenology as well as novel aspects of QED under extreme conditions [65][66][67][68][69][70].…”