Two-loop triangle integrals with 4 scales for the $HZV$ vertex

Abstract

We calculate analytically the two-loop triangle integrals entering the $\mathcal{O}(\alpha {\alpha }_s)$ corrections to the $HZV$ vertex with $V=Z^{\ast },{\gamma }^{\ast }$ using the method of differential equations. Our result provides a prototype to study the analytic properties of multi-loop multi-scale Feynman integrals, and also allows fast numeric evaluation for phenomenological studies. We apply our results to the leptonic decay of the Higgs boson and to $ZH$ production at electron-positron colliders. Besides the top quark loop, we include also the bottom quark loop contributions, whose evaluation takes a lot of time using purely numeric methods, but is very efficient with our analytic results.

Comments: 5 pages, 4 figures