Exclusive $J/ψ+γ$ production in ultraperipheral ion collisions

Abstract: Ultraperipheral collisions (UPCs) of ions provide new opportunities to study the quarkonium production mechanism in photon-photon scattering. In this paper, we investigate the exclusive process $\gamma+\gamma\to J/\psi+\gamma$ up to $\mathcal{O}(\alpha_s v^2)$ accuracy within the nonrelativistic quantum chromodynamics factorization framework. We evaluate the corresponding cross sections for Pb-Pb and p-p UPCs at the Large Hadron Collider. Numerical results show that the $\mathcal{O}(\alpha_s)$, $\mathcal{O}(v^2)$, and $\mathcal{O}(\alpha_s v^2)$ corrections are about $-50\%$, $-33\%$, and $15\%$ of the leading-order (LO) contribution, respectively, showing reasonable convergence in both $\alpha_s$ and $v^2$ expansion. Collectively, these corrections suppress the LO cross section by a factor of about $1/3$, which is a crucial effect for reliable phenomenological analysis. Our results suggest that future experimental measurements of this process are feasible.