${{\mathit H}}$ SIGNAL STRENGTHS IN DIFFERENT CHANNELS
The ${{\mathit H}}$ signal strength in a particular final state ${{\mathit x}}{{\mathit x}}$ is given by the cross section times branching ratio in this channel normalized to the Standard Model (SM) value, $\sigma $ $\cdot{}$ B( ${{\mathit H}}$ $\rightarrow$ ${{\mathit x}}{{\mathit x}}$) $/$ ($\sigma $ $\cdot{}$ B( ${{\mathit H}}$ $\rightarrow$ ${{\mathit x}}{{\mathit x}}))_{{\mathrm {SM}}}$, for the specified mass value of ${{\mathit H}}$. For the SM predictions, see DITTMAIER 2011, DITTMAIER 2012, and HEINEMEYER 2013A. Results for fiducial and differential cross sections are also listed below.
${{\mathit \gamma}^{*}}{{\mathit \gamma}}$ final state
INSPIRE search
1AAD 2021I search for ${{\mathit H}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \ell}}{{\mathit \gamma}}$ (${{\mathit \ell}}$ = ${{\mathit e}}$ , ${{\mathit \mu}}$) in 139 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 13 TeV. The mass of dilepton ${{\mathit m}}_{{{\mathit \ell}} {{\mathit \ell}}}$ is smaller than 30 GeV. This region is dominated by the decay through ${{\mathit \gamma}^{*}}$. The quoted signal strength corresponds to a significance of 3.2 standard deviations and is given for ${\mathit m}_{{{\mathit H}}}$ = 125.09 GeV. The cross section times the branching ratio of ${{\mathit H}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \ell}}{{\mathit \gamma}}$ for ${{\mathit m}}_{{{\mathit \ell}} {{\mathit \ell}}}<$ 30 GeV is measured to be $8.7$ $\pm2.7$ ${}^{+0.7}_{-0.6}$ fb.
2SIRUNYAN 2018DQ search for ${{\mathit H}}$ $\rightarrow$ ${{\mathit \gamma}^{*}}{{\mathit \gamma}}$, ${{\mathit \gamma}^{*}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \mu}}$ in 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 13 TeV. The mass of ${{\mathit \gamma}^{*}}$ is smaller than 50 GeV except in ${{\mathit J / \psi}}$ and ${{\mathit \Upsilon}}$ mass regions. The quoted signal strength (see their Figs. 6 and 7) is given for ${\mathit m}_{{{\mathit H}}}$ = 125 GeV.
3KHACHATRYAN 2016B search for ${{\mathit H}}$ $\rightarrow$ ${{\mathit \gamma}^{*}}{{\mathit \gamma}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit \gamma}}$ and ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}{{\mathit \gamma}}$ (with m(${{\mathit e}^{+}}{{\mathit e}^{-}}$) $<$ 3.5 GeV and m(${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$) $<$ 20 GeV) in 19.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. See their Fig. 6 for limits on individual channels.
References:
AAD
2021I
PL B819 136412
Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at s=13 TeV with the ATLAS detector
SIRUNYAN
2018DQ
JHEP 1811 152
Search for the decay of a Higgs boson in the $\ell\ell\gamma$ channel in proton-proton collisions at $\sqrt{s} =$ 13 TeV
KHACHATRYAN
2016B
PL B753 341
Search for a Higgs Boson Decaying into ${{\mathit \gamma}^{*}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \ell}}{{\mathit \gamma}}$ with Low Dilepton Mass in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV