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The current theoretical estimations lead to cross-sections for $AA\to\gamma\gamma AA$ which are smaller than the measured ones by the ATLAS and CMS Collaborations, which motivates for calculation of subleading corrections. In our last paper[1] we estimated for the first time the contribution of inelastic channels to the LbL scattering in ultraperipheral collisions, in which one or both of the nuclei dissociate. These new mechanisms are related to extra emissions that are difficult to identify and may be misinterpreted as enhanced $\gamma\gamma$ scattering compared to the standard result.
We include processes of coupling of photons to individual nucleons in addition to coherent coupling. Both elastic and inelastic with couplings of photons to nucleons are taken into account. The inelastic photon fluxes are shown and compared to standard fluxes in the nucleus. We show the ratio of the inelastic corrections to the standard contribution as a function of diphoton invariant mass and photon rapidity difference. Our results indicate that the inelastic contributions is of the order of 20-40% of the coherent production. Uncertainties due to factorization scale choice are quantified. The discussion how to eliminate or measure the inelastic contributions will be presented.
[1] M. Klusek-Gawenda, V.P. Goncalves and A. Szczurek,
Phys.Lett.B867(2025)139614.
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