Differential cross sections for exclusive dielectron production, in the fiducial phase space of Table 1, as functions of the pair invariant mass. Data are compared with SUPERCHIC + FSR(PHOTOS++), STARLIGHT + FSR(PY8), and gamma-UPC + FSR(PY8) predictions.

Differential cross sections for exclusive dielectron production, in the fiducial phase space of Table 1, as functions of the pair |cos $\theta$*|. Data are compared with SUPERCHIC + FSR(PHOTOS++), STARLIGHT + FSR(PY8), and gamma-UPC + FSR(PY8) predictions.

Differential exclusive diphoton cross sections in the fiducial phase space of Table 1 as a function of the diphoton rapidity measured in data compared with SUPERCHIC and gamma-UPC@NLO predictions.

Differential exclusive diphoton cross sections in the fiducial phase space of Table 1 as a function of the diphoton invariant mass measured in data compared with SUPERCHIC and gamma-UPC@NLO predictions.

Observed and expected 95% CL limits on the production cross section $\sigma(\gamma\gamma \rightarrow a \rightarrow \gamma\gamma)$ as a function of the ALP mass $m_{a}$. The uncertainties indicate regions containing 68 and 95% of the distribution of limits expected under the background-only hypothesis. The additional datasets indicate the expected ALP cross sections as a function of $m_{a}$ for decreasing photon couplings ($g_{a\gamma} = 0.3, 0.1, 0.05 TeV^{-1}$).

Exclusion limits at 95% CL in the axion-photon coupling $g_{a\gamma}$ versus axion mass $m_a$ plane, for the operator $\frac{1}{4\Lambda}aF\widetilde{F}$ (assuming ALPs coupled only to photons) extracted in this analysis.

Upper limits on $\mathcal{B}(H\rightarrow aa\rightarrow 4\gamma)$ at 95% CL as a function of the axion mass and for ALP-photon coupling $C_{a\gamma\gamma}=0.01$.

Upper limits on $\mathcal{B}(H\rightarrow aa\rightarrow 4\gamma)$ at 95% CL as a function of the axion mass and for ALP-photon coupling $C_{a\gamma\gamma}=5\times10^{-4}$

Upper limits on $\mathcal{B}(H\rightarrow aa\rightarrow 4\gamma)$ at 95% CL as a function of the axion mass and for ALP-photon coupling $C_{a\gamma\gamma}=10^{-5}$

Upper limits on $B(H\rightarrow 4\gamma)$ at 95% CL as a function of the signal mass hypothesis and for the assumption of promptly decaying ALPs.

Identification efficiency for isolated photons that pass the tight photon ID requirements in dependence of the opening angle in $\Delta R$ of both decay photons of the axion and the decay radius of the originating axion from the primary vertex for axions with masses between 100 MeV and 300 MeV. All four axion decay photons on MC truth level are required to fulfil $|\eta|<2.5$ and $p_T>5$ GeV. Only a mild dependency on the decay radius can be seen, since the distance between the two photons is small and hence the combined decay signature in the calorimeter still points to the primary vertex.

Efficiency for classified merged isolated photons in dependence of the opening angle in $\Delta R$ of both decay photons of the axion and the decay radius of the originating axion from the primary vertex for axions with masses between 100 MeV and 300 MeV. All four axion decay photons on MC truth level are required to fulfil $|\eta|<2.5$ and $p_T>5$ GeV. Only a mild dependency on the decay radius can be seen, since the distance between the two photons is small and hence the combined decay signature in the calorimeter still points to the primary vertex.

Limits on the ALP mass and coupling to photons at 95\%~CL, assuming $\mathcal{B}(a\rightarrow\gamma\gamma) = 1$, $\Lambda = 1\,TeV$ with $|C_{aH}^{\text{eff}}|$ = $1$ (solid line) and $|C_{aH}^{\text{eff}}|$ = $0.1$.

The number of data and estimated background events in the signal region of the most sensitive categories..

Background-only fit to the observed numbers of events (black points) as a function of the diphoton invariant mass $m_{\gamma\gamma}$.

Expected and observed 95% CL upper limits on the signal fiducial cross section $\sigma_{\textrm{fid}}$, assuming 100% branching ratio for ALP decay into two photons, as a function of the hypothetical ALP mass $m_{\textrm{X}}$. The 1$\sigma$ and 2$\sigma$ confidence intervals are shown by the coloured bands.

Expected and observed 95% CL upper limits on the the ALP coupling constant, assuming 100% branching ratio for ALP decay into two photons, as a function of the hypothetical ALP mass $m_{\textrm{X}}$. The 1$\sigma$ and 2$\sigma$ confidence intervals are shown by the coloured bands. Contours of the ALP natural width $\Gamma$ are illustrated by the smooth blue solid lines.

Fiducial region acceptance of signal events for coupling constant f$^{-1}=0.05$ TeV$^{-1}$. EL, SD, and DD stand for the exclusive, single-dissociative, and double-dissociative processes. The acceptances are parameterised as $p_0 + p^{i}_{1} e^{p_{2}^{i} m_{\textrm{X}}} + p_{3}^{i} e^{p_{4}^{i} m_{\textrm{X}}} $ , where $i$ specifies the process type, exclusive, single-dissociative, or double-dissociative.

Correction factors $A_{\textrm{X}}/A_{0}$ and $C_{\textrm{X}}$ for the exclusive signal events with ALP coupling constant f$^{-1}$=0.05 TeV$^{-1}$, where acceptance $A_{\textrm{X}}$ and efficiency $C_{\textrm{X}}$ are defined in arXiv:2102.13405. $A_{\textrm{X}}$/$A_{0}$ and $C_{\textrm{X}}$ are parameterised as $p_0 + p^{i}_{1} e^{p_{2}^{i} m_{\textrm{X}}} + p_{3}^{i} e^{p_{4}^{i} m_{\textrm{X}}}$, where $i$ specifies the process type.

Simulated ALP signal cutflow for $m_{\rm{X}}$=300 GeV and $m_{\rm{X}}$=1200 GeV. The yields are normalized to a luminosity of 14.6 fb$^{-1}$. Selections are applied for each side after the selection on acoplanarity. The union of the sets of selected events is taken finally.

SR1 diboson invariant mass distribution in the resolved tagged category after fitting the signal and sideband regions using a signal (ALP linear ZZ) plus background model. The last bin includes events with diboson invariant masses up to 3000 GeV. The signal is normalized to the 95% CL cross section limit at $f_a$ = 3 TeV (the scale factor used in the original figure for better visibility is not applied here).

SR2 diboson invariant mass distribution in the boosted untagged category after fitting the signal and sideband regions using a signal (ALP chiral ZH) plus background model. The last bin includes events with diboson invariant masses up to 3000 GeV. The signal is normalized to the 95% CL cross section limit at $f_a$ = 3 TeV (the scale factor used in the original figure for better visibility is not applied here).

SR2 diboson invariant mass distribution in the boosted tagged category after fitting the signal and sideband regions using a signal (ALP chiral ZH) plus background model. The last bin includes events with diboson invariant masses up to 3000 GeV. The signal is normalized to the 95% CL cross section limit at $f_a$ = 3 TeV.

SR2 diboson invariant mass distribution in the resolved untagged category after fitting the signal and sideband regions using a signal (ALP chiral ZH) plus background model. The last bin includes events with diboson invariant masses up to 3000 GeV. The signal is normalized to the 95% CL cross section limit at $f_a$ = 3 TeV (the scale factor used in the original figure for better visibility is not applied here).

SR2 diboson invariant mass distribution in the resolved tagged category after fitting the signal and sideband regions using a signal (ALP chiral ZH) plus background model. The last bin includes events with diboson invariant masses up to 3000 GeV. The signal is normalized to the 95% CL cross section limit at $f_a$ = 3 TeV (the scale factor used in the original figure for better visibility is not applied here).

Observed and expected 95% CL upper limit on $\sigma \mathcal{B}$(G -> ZZ) as a function of the resonance mass, taking into account all statistical and systematic uncertainties. The electron and muon channels and the various categories used in the analysis are combined. The inner green band and the outer yellow band represent the 68 and 95% coverage of the expected limits in the background-only hypothesis.

Observed and expected 95% CL upper limit on $\sigma \mathcal{B}$(W' -> ZW) as a function of the resonance mass, taking into account all statistical and systematic uncertainties. The electron and muon channels and the various categories used in the analysis are combined. The inner green band and the outer yellow band represent the 68 and 95% coverage of the expected limits in the background-only hypothesis.

Observed and expected 95% CL upper limit on the product of the ALP coupling to gluons and the coupling to Z bosons as a function of the mass scale $f_a$ for ALP masses smaller than 100 GeV.

Observed and expected 95% CL upper limit on the product of the ALP coupling to gluons and the chiral $a_\widetilde{2D}$ coupling as a function of the mass scale $f_a$ for ALP masses smaller than 100 GeV.