Direct Access to Nuclear Photon TMDs with In Situ Probes in Ultraperipheral Heavy-Ion Collisions
Year: 2026
Type: preprint
Abstract: Resolving local structure in photon distributions is an important goal in probing strong coherent electromagnetic fields. We propose using electron--positron pairs produced in situ in ultraperipheral heavy-ion collisions as dynamical probes to directly extract photon distributions. We define a theoretical reference cross section using the complete tree-level amplitude for two-photon-induced radiative lepton-pair production. When background effects factorize into a scalar Bose-enhancement factor, the ratio of the background-modified to reference differential cross sections, minus unity, yields the photon occupation number at a fixed momentum. Finite bins yield averages weighted by the reference cross section. We specify the conditions under which kinematic selections, acceptance, and radiative corrections preserve this local inversion.
Source: arXiv (Cornell University)
Author: Li, Cong
Institution: Zhejiang Ocean University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223244491