# Interplay of Reggeon and photon in pA collisions

We discuss the effects of the electromagnetic interaction in high-energy proton collisions with nuclei of large Z at strong coupling $\lambda=g^2N_c$. Using the holographic dual limit of large $N_c>\lambda\gg 1$, we describe the Reggeon exchange as a twisted surface and show that it gets essentially modified by the electromagnetic interaction.

**Comments:**19 pages, 4 figures

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**Affiliations:**

^{1}Ecole polytechnique, CPHT

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