Two-loop QCD corrections for real and off-shell diphoton and triphoton production via quark loops

Journal article

We compute squared matrix elements at next-to-next-to-leading order in perturbative quantum chromodynamics for the production of two or three (on- or off-shell) photons mediated via (light or heavy) quark loops. Our method handles all cases in a unified framework, using simultaneous subtraction of infrared, ultraviolet, and threshold singularities in loop momentum space to produce a locally finite integrand suitable for numerical integration. We confirm agreement with available analytic benchmarks at fixed phase-space points and provide new results otherwise. We also compute the double-virtual corrections to the cross section for on- and off-shell diphoton and on-shell triphoton production by combining the Monte Carlo integration over loop and phase space.

Authors: Kermanschah, D; Vicini, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2026
• Issue: 3
• Article number: 4
• Publication date: 2026-03-02
• Acceptance date: 2026-01-14
• DOI: 10.1007/jhep03(2026)004
• EISSN: 1029-8479
• ISSN: 1126-6708
• Language: English
• Keywords: Higher-Order Perturbative Calculations; Quark Masses; Automation