Search for a Higgs boson decaying into γ⁎γ→ℓℓγ with low dilepton mass in pp collisions at s=8 TeV

Search for rare decays of $$\mathrm {Z}$$ Z and Higgs bosons to $${\mathrm {J}/\psi } $$ J / ψ and a photon in proton-proton collisions at $$\sqrt{s}$$ s = 13 $$\,\text {TeV}$$ TeV

“…The results from our H → J/ψγ analysis are combined with the results from a similar search performed by the CMS Collaboration using pp collision data at √ s = 8 TeV, corresponding to an integrated luminosity of 19.7 fb −1 [20]. The combination results in an upper limit corresponding to 220 (160) times the SM prediction.…”

“…The respective observed and expected upper limits at 95% confidence level (CL) on the branching fraction were reported to be 2.6 and 2.0 +1.0 −0.6 × 10 -6 , where the subscript and superscript reflect the range in the 68% central-quantiles of upper limits assuming a background-only hypothesis. Searches for the H → J/ψγ decay were performed by AT-LAS and CMS in pp collisions collected at √ s = 8 TeV [19,20]. The respective observed and expected upper limits in the branching fractions were 1.5 and 1.2 +0.6 −0.3 × 10 -3 from ATLAS, and 1.5 and 1.6 +0.8 −0.8 × 10 -3 from CMS.…”

Higgs Boson Properties

“…In addition to the Higgs boson decay modes summarised in Table 1 44 and H → V γ 44,45 with V = J/ψ, Υ. Even with small expected branching fractions in the SM, effects beyond the SM (BSM) could result in enhanced branching fractions and thus an observable signal.…”

Charm-quark Yukawa coupling in h→cc¯γ at LHC

“…A second approach used exclusive decays of the Higgs into a J/ψ and a photon [23]. While this final state can be well-separated from backgrounds in the J/ψ → µ + µ − channel [24][25][26], it suffers from a small branching ratio and modeling assumptions to extract the Higgs-charm Yukawa. In particular, the leading contribution to this process is via the vector meson dominance γ * → J/ψ, which is an order of magnitude larger than that involving the charm-quark Yukawa coupling [23,27,28], leading to a less sensitive upper bound on y c of about 50 times of the SM prediction at the HL-LHC [29].…”