A note on Higgs decays into $Z$ boson and $J/\Psi ({\rm Y})$

Abstract

Rare decays $h\to ZV$ with $V$ denoting the narrow $c\bar{c}$ or $b\bar{b}$ resonances, such as $J/\Psi$ or ${\rm Y}$ states, have been analyzed. Within the standard model, these channels may proceed through the tree-level transition $h\to Z{Z}^{\ast }$ with the virtual $Z^{\ast }\to V$, and also loop-induced process $h\to Z{\gamma }^{\ast }$, followed by ${\gamma }^{\ast }\to V$. Our analysis shows that, for the bottomonium final states, the decay rate of $h\to Z{\rm Y}$ from the loop-induced process is small and the former transition gives the dominant contribution; while, for the charmonium final states, $\Gamma (h\to ZJ/\Psi )$ and $\Gamma (h\to Z\Psi (2S))$ induced by $h\to Z{\gamma }^{\ast }\to ZV$ could be comparable to the contribution given by the tree-level $h\to Z{Z}^{\ast }\to ZV$ transition.

Comments: 6 pages, 2 figures