Relativistic corrections to Higgs boson decays to quarkonia

Original · EN

We improve the theoretical predictions for the decays of the Higgs boson to an S-wave vector quarkonium plus a photon by calculating the relativistic correction of order v², where v is the heavy-quark velocity in the quarkonium rest frame. Our numerical results are given for the J/ψ and Υ(nS) channels, with n=1,2,3. The numerical results include a previously calculated correction of order αₛ and summations, to all orders in αₛ, of leading logarithms of mₕ²/mQ², where mₕ is the Higgs-boson mass and mQ is the heavy-quark mass. These QCD corrections apply to the contribution of leading order in v and to part of the order-v² correction. For the remainder of the order-v² correction, we sum leading logarithms of mₕ/mQ through order αₛ². These refinements reduce the theoretical uncertainties in the direct-production amplitudes for H → J/ψ+γ and H → Υ(1S)+γ by approximately a factor of 3 and open the door to improved determinations at the LHC of the Higgs-boson Yukawa couplings to the charm and bottom quarks.