Amplitude-level NLO predictions for exclusive $J/ψ+γ$ production in ultraperipheral collisions
Year: 2026
Type: preprint
Abstract: Exclusive $γγ\to J/ψ+γ$ production is studied in the color-singlet channel at leading order in the heavy-quark velocity. The conventional next-to-leading-order (NLO) result $B+V$, comprising Born production and its interference with the renormalized one-loop amplitude, is compared with $B+V+Q$, where $Q$ retains the complete one-loop square. At photon-photon energies $W=80~\mathrm{GeV}$ and $160~\mathrm{GeV}$, the conventional spectrum becomes negative over finite high-$p_T$ intervals already at renormalization scale $μ_R=W$, whereas the complete square remains non-negative. In contrast, the total partonic cross section exceeds Born at the larger energies in the energy scan, owing to positive virtual contributions from other scattering directions. For $p$-$p$ collisions at $14~\mathrm{TeV}$ and $Pb$-$Pb$ collisions at $\sqrt{s_{NN}}=5.52~\mathrm{TeV}$, $Q$ raises the central integrated ultraperipheral rates by $11.6\%$--$18.4\%$. Their absolute scale widths over $μ_R=\{W/2,W,2W\}$ decrease by $36\%$--$67\%$. Retaining the complete one-loop square changes both the predicted integrated rates and the shapes of the differential distributions.
Source: arXiv (Cornell University)
Authors: Zhan, Xi-Jie, Feng, Tai-Fu, Wu, Xing-Gang
Institution: Chongqing University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G5913328413, G7223305753, G7902198378
OpenAlex ID: W7220709763