Divector boson production in association with a Higgs boson at hadron colliders

Abstract

We consider the production of a Higgs boson in association with two electroweak vector bosons at hadron colliders. In particular, we examine $\gamma\gamma H$, $\gamma ZH$, $ZZH$, and $W^{+}W^{-}H$ production at the LHC (14 TeV), HE-LHC (27 TeV), and FCC-hh (100 TeV) colliders. Our main focus is to estimate the gluon-gluon ($gg$) channel ($gg \to VV^\prime H$) contributions to $pp \to VV^\prime H~(V,V^\prime=\gamma,Z,W)$ and compare them with corresponding contributions arising from the quark-quark ($qq$) channel. Technically, the leading order $gg$ channel contribution to $pp \to VV^\prime H$ cross section is an NNLO correction in $\alpha_s$. In the processes under consideration, we find that in the $gg$ channel, $W^{+}W^{-}H$ has the largest cross section. However, relative contribution of the $gg$ channel is more important for the $pp \to ZZH$ production. At the FCC-hh, $gg \to ZZH$ contribution is comparable with the NLO QCD correction to $qq \to ZZH$. We also compute the cross sections when $W$ and $Z$-bosons are polarized. In the production of $W^{+}W^{-}H$ and $ZZH$, we find that the $gg$ channel contributes more significantly when the vector bosons are longitudinally polarized. By examining such events, one can increase the fraction of the $gg$ channel contribution to these processes. Further, we have studied beyond-the-standard-model effects in the $\kappa$-framework. We find that the $gg$ channel processes $ZZH$ and $WWH$ have very mild dependence on $\kappa_\lambda$, but strong dependence on $\kappa_t$ and $\kappa_V$. The $qq$ channel processes mainly depend on $\kappa_V$. Dependence of the $gg$ channel contribution on $\kappa_V$ is stronger than that of the $qq$ channel contribution. Therefore focusing on events with longitudinally polarized $W$ and $Z$-bosons, one can find stronger dependence on $\kappa_V$ that can help us measure this parameter.