Higgs boson decay to charmonia via $c$-quark fragmentation

Abstract

We calculate the decay branching fractions of the Higgs boson to $J/\psi$ and ${\eta }_c$ via the charm-quark fragmentation mechanism for the color-singlet and color-octet states in the framework of non-relativistic QCD. The decay rates are governed by the charm-quark Yukawa coupling, unlike the decay $H\to J/\psi +\gamma$, which is dominated by the ${\gamma }^{\ast }$-$J/\psi$ mixing. We find that the decay branching fractions can be about $2\times 10^{-5}$ for $H\to c\bar{c}+J/\psi$, and $6\times 10^{-5}$ for $H\to c\bar{c}+{\eta }_c$. We comment on the perspective of searching for the Higgs boson to $J/\psi$ transition at the High-Luminosity LHC for testing the charm-quark Yukawa coupling.

Comments: Updated the discussion on the $y_c$ sensitivity, to be published on JHEP