One-loop Form Factors for \(H\rightarrow \gamma^*\gamma^*\) in \(R_{\xi}\) Gauge

In this paper, we present general one-loop form factors for \(H\rightarrow \gamma^* \gamma^*\) in \(R_{\xi}\) gauge, considering all cases of two on-shell, one on-shell and off-shell final photons. The calculations are performed standard model arbitrary beyond the models which charged scalar particles may be exchanged diagrams. Analytic results shown forms expressed terms Passarino-Veltman functions. We also confirm previous computations available case \(\xi\)-independent result is discussed. find that numerical good stability with varying \(\xi=0,1\) \(\xi\rightarrow \infty\).