90% CL upper limit in axion-like particle coupling to SM fermions at UV scale Lambda=1TeV vs mass parameter space for di-lepton final states.

90% CL upper limit in axion-like particle coupling to SM gluons at UV scale Lambda=1TeV vs mass parameter space for hadronic final states.

Number of expected $a \to K^+K^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $C_{bs}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\eta$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $C_{bs}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\gamma$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $C_{bs}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $C_{bs}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $C_{bs}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\pi^0$ assuming production coupling $\theta_{\pi^0} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\pi^0$ assuming production coupling $\theta_{\pi^0} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to K^+K^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\pi^0$ assuming production coupling $\theta_{\pi^0} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\eta$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\pi^0$ assuming production coupling $\theta_{\pi^0} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\gamma$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\pi^0$ assuming production coupling $\theta_{\pi^0} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\pi^0$ assuming production coupling $\theta_{\pi^0} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\pi^0$ assuming production coupling $\theta_{\pi^0} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to K^+K^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\eta$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\gamma$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta^\prime$ assuming production coupling $\theta_{\eta^\prime} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta^\prime$ assuming production coupling $\theta_{\eta^\prime} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to K^+K^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta^\prime$ assuming production coupling $\theta_{\eta^\prime} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\eta$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta^\prime$ assuming production coupling $\theta_{\eta^\prime} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\gamma$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta^\prime$ assuming production coupling $\theta_{\eta^\prime} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta^\prime$ assuming production coupling $\theta_{\eta^\prime} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta^\prime$ assuming production coupling $\theta_{\eta^\prime} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for Primakoff production assuming production coupling $C_{\gamma\gamma}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for Primakoff production assuming production coupling $C_{\gamma\gamma}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to K^+K^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for Primakoff production assuming production coupling $C_{\gamma\gamma}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\eta$ events for BR = 1 in the plane (mass, width) after full selection, for Primakoff production assuming production coupling $C_{\gamma\gamma}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\gamma$ events for BR = 1 in the plane (mass, width) after full selection, for Primakoff production assuming production coupling $C_{\gamma\gamma}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for Primakoff production assuming production coupling $C_{\gamma\gamma}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $a \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for Primakoff production assuming production coupling $C_{\gamma\gamma}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to K^+K^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to K^+K^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for mixing production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for mixing production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to K^+K^-$ events for BR = 1 in the plane (mass, width) after full selection, for mixing production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to K^+K^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for mixing production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-$ events for BR = 1 in the plane (mass, width) after full selection, for mixing production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for mixing production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for mixing production assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in light meson decays assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in light meson decays assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in light meson decays assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in light meson decays assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $A^\prime \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for production in light meson decays assuming production coupling $\varepsilon=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to K^+K^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to \pi^+\pi^-$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to \pi^+\pi^-\pi^0\pi^0$ events for BR = 1 in the plane (mass, width) after full selection, for Bremsstrahlung production assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to \mu^+\mu^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to K^+K^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

Number of expected $S \to \pi^+\pi^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $\mathrm{sin}^2\theta=1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

95% CL expected and observed exclusion limits on the branching ratio of the Higgs boson to dark photons as a function of the γ_d mass for the HAHM model.

95% CL expected and observed exclusion limits on the branching ratio of the Higgs boson to dark photons as a function of the γ_d mass for the FRVZ model.

90% CL exclusion limit contours on the branching ratio of the Higgs boson to dark photons as functions of the γ_d mass and kinetic mixing parameter ε for the HAHM model. These exclusions assume Higgs boson branching fractions to dark photons within a 0.01% and 10% range.

90% CL exclusion limit contours on the branching ratio of the Higgs boson to dark photons as functions of the γ_d mass and kinetic mixing parameter ε for the FRVZ model. These exclusions assume Higgs boson branching fractions to dark photons within a 0.01% and 10% range.

The reconstruction efficiency for μLJ objects produced in the decay of a γ_d into a muon pair. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the HAHM signal model. The efficiency is shown as a function of the dark photon p_T.

The reconstruction efficiency for μLJ objects produced in the decay of a γ_d into a muon pair. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the FRVZ signal model. The efficiency is shown as a function of the dark photon p_T.

The reconstruction efficiency for μLJ objects produced in the decay of a γ_d into a muon pair. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the HAHM signal model. The efficiency is shown as a function of the ΔR opening between the decay products of a dark photon.

The reconstruction efficiency for μLJ objects produced in the decay of a γ_d into a muon pair. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the FRVZ signal model. The efficiency is shown as a function of the ΔR opening between the decay products of a dark photon.

The reconstruction efficiency for μLJ objects produced in the decay of a γ_d into a muon pair. The reconstruction efficiency is shown for a dark photon mass of 0.4 GeV, generated according to the HAHM and FRVZ signal models. The efficiency is shown as a function of the γ_d p_T.

The reconstruction efficiency for μLJ objects produced in the decay of a γ_d into a muon pair. The reconstruction efficiency is shown for a dark photon mass of 0.4 GeV, generated according to the HAHM and FRVZ signal models. The efficiency is shown as a function of the ΔR opening between the decay products of a dark photon.

The reconstruction efficiency for eLJ objects produced in the decay of a γ_d into an electron pair. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the HAHM signal model. The efficiency is shown as a function of the dark photon p_T.

The reconstruction efficiency for eLJ objects produced in the decay of a γ_d into an electron pair. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the FRVZ signal model. The efficiency is shown as a function of the dark photon p_T.

The reconstruction efficiency for eLJ objects produced in the decay of a γ_d into a pair of electrons. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the HAHM signal model. The efficiency is shown as a function of the ΔR opening between the decay products of a dark photon. The decrease in efficiency, visible at 0.1, is due to the transition between the region of the phase space where eLJs are identified from merged EM showers with two tracks, to the one where eLJs are obtained by the clustering of two resolved electrons.

The reconstruction efficiency for eLJ objects produced in the decay of a γ_d into a pair of electrons. The reconstruction efficiency is shown for different dark photon mass hypotheses generated according to the FRVZ signal model. The efficiency is shown as a function of the ΔR opening between the decay products of a dark photon. The decrease in efficiency, visible at 0.1, is due to the transition between the region of the phase space where eLJs are identified from merged EM showers with two tracks, to the one where eLJs are obtained by the clustering of two resolved electrons.

The reconstruction efficiency for eLJ objects produced in the decay of a γ_d into a pair of electrons. The reconstruction efficiency is shown for a dark photon mass of 0.1 GeV, generated according to the HAHM and FRVZ signal models. The efficiency is shown as a function of the γ_d p_T.

The reconstruction efficiency for eLJ objects produced in the decay of a γ_d into a pair of electrons. The reconstruction efficiency is shown for a dark photon mass of 0.1 GeV, generated according to the HAHM and FRVZ signal models. The efficiency is shown as a function of the ΔR opening between the decay products of a dark photon.

95% CL expected and observed exclusion limits on the branching ratio of the Higgs boson to dark photons as a function of the γ_d mass for the HAHM model, obtained from the μLJ–μLJ signal region.

95% CL expected and observed exclusion limits on the branching ratio of the Higgs boson to dark photons as a function of the γ_d mass for the FRVZ model, obtained from the μLJ–μLJ signal region.

95% CL expected and observed exclusion limits on the branching ratio of the Higgs boson to dark photons as a function of the γ_d mass for the HAHM model, obtained from the μLJ–eLJ signal region.

95% CL expected and observed exclusion limits on the branching ratio of the Higgs boson to dark photons as a function of the γ_d mass for the FRVZ model, obtained from the μLJ–eLJ signal region.

Acceptance times efficiencies (A×ϵ) as a function of the γ_d mass for the HAHM process for the three signal regions of the analysis, eLJ-eLJ, eLJ-μLJ and μLJ-μLJ. The decrease of the A×ϵ is expected for increasing masses of the γ_d, as its decay products become resolved and are no longer reconstructed as LJs. The local minimum around m_{γ_d}=2 GeV observed for the eLJ-μLJ distribution is expected, as the reconstruction efficiency for eLJs with merged EM showers decreases before the reconstruction of eLJ with two resolved electrons becomes efficient.

Acceptance times efficiencies (A×ϵ) as a function of the γ_d mass for the FRVZ process for the three signal regions of the analysis, eLJ-eLJ, eLJ-μLJ and μLJ-μLJ. The decrease of the A×ϵ is expected for increasing masses of the γ_d, as its decay products become resolved and are no longer reconstructed as LJs. The local minimum around m_{γ_d}=2 GeV observed for the eLJ-μLJ distribution is expected, as the reconstruction efficiency for eLJs with merged EM showers decreases before the reconstruction of eLJ with two resolved electrons becomes efficient.

90% confidence level expected exclusion contour in the B-L gauge boson parameter space.

Selection efficiencies for dark photon signal events decaying within the FASER acceptance with a radius < 10 cm as a function of dark photon mass and kinematic mixing.

Measured min-$d_{xy}$ distribution in the 2-match category, after requiring the $d_{xy}$ muon to pass the isolation requirement $I_{\mathrm{rel}}^{\mathrm{PF}} <0.25$ (i. e., the B and D bins of the ABCD plane). Overlaid with a red histogram is the background predicted from the region of the ABCD plane failing the same requirement (the A and C bins), as well as three signal benchmark hypotheses (as defined in the legends), assuming $\alpha_D = \alpha_{\mathrm{EM}}$ (the fine-structure constant). The red hatched bands correspond to the background prediction uncertainty. The last bin includes the overflow.

Two-dimensional exclusion surfaces for $\Delta = 0.1 \, m_1$ as a function of the DM mass $m_1$ and the signal strength $y$, with $m_{A'} = 3 \, m_1$. Filled histograms denote observed limits on $\sigma(\mathrm{pp} \to A' \to \chi_2 \chi_1) \, \mathcal{B}(\chi_2 \to \chi_1 \mu^+ \mu^-)$. Solid (dashed) curves denote the observed (expected) exclusion limits at 95% CL, with 68% CL uncertainty bands around the expectation. Regions above the curves are excluded, depending on the $\alpha_D$ hypothesis: $\alpha_{\mathrm{D}} = \alpha_{\mathrm{EM}}$ (dark blue) or 0.1 (light magenta).

Two-dimensional exclusion surfaces for $\Delta = 0.4 \, m_1$ as a function of the DM mass $m_1$ and the signal strength $y$, with $m_{A'} = 3 \, m_1$. Filled histograms denote observed limits on $\sigma(\mathrm{pp} \to A' \to \chi_2 \chi_1) \, \mathcal{B}(\chi_2 \to \chi_1 \mu^+ \mu^-)$. Solid (dashed) curves denote the observed (expected) exclusion limits at 95% CL, with 68% CL uncertainty bands around the expectation. Regions above the curves are excluded, depending on the $\alpha_D$ hypothesis: $\alpha_{\mathrm{D}} = \alpha_{\mathrm{EM}}$ (dark blue) or 0.1 (light magenta).

The reconstruction efficiency for caloDPJs produced by the decay of &gamma;_d into e⁺e^- or qq&#772;. The reconstruction efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as a function of their transverse momentum in events where the &gamma;_d L_xy is between 2&nbsp;m and 4&nbsp;m.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d+X and ggF selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_2&mu;^ggF, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d+X is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d+X and ggF selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_c+&mu;^ggF, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d+X is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d+X and ggF selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_2c^ggF, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d+X is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d+X and WH selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_c^WH, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d+X is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d+X and WH selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_c+&mu;^WH, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d+X is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d+X and WH selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_2c^WH, assuming an FRVZ signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d+X is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d and ggF selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_2&mu;^ggF, assuming a HAHM signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d and ggF selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_c+&mu;^ggF, assuming a HAHM signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d is larger than unity.

Observed 95% CL upper limits on the branching ratio (B) for the decay H&rarr;&nbsp;2&gamma;_d and ggF selection, for different &gamma;_d masses and a 125&nbsp;GeV Higgs boson. The limits are shown for the SR_2c^ggF, assuming a HAHM signal model. The hatched band denotes the region in which the branching ratio of H&rarr;&nbsp;2&gamma;_d is larger than unity.

The CalRatio 2015--2016 trigger efficiency for the decay of &gamma;_d in e⁺e^- or qq&#772;. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse decay length L_xy.

The CalRatio 2015--2016 trigger efficiency for the decay of &gamma;_d in e⁺e^- or qq&#772;. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse momentum, in events where the &gamma;_d L_xy is between 2&nbsp;m and 4&nbsp;m.

The CalRatio 2017--2018 trigger efficiency for the decay of &gamma;_d in e⁺e^- or qq&#772;. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse decay length L_xy.

The CalRatio 2017--2018 trigger efficiency for the decay of &gamma;_d in e⁺e^- or qq&#772;. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse momentum, in events where the &gamma;_d L_xy is between 2&nbsp;m and 4&nbsp;m.

The narrow-scan 2015--2016 trigger efficiency for the decay of &gamma;_d in &mu;⁺&mu;^-. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse decay length L_xy.

The narrow-scan 2015--2016 trigger efficiency for the decay of &gamma;_d in &mu;⁺&mu;^-. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse momentum, in events where the &gamma;_d L_xy is below 6&nbsp;m.

The narrow-scan 2017--2018 trigger efficiency for the decay of &gamma;_d in &mu;⁺&mu;^-. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse decay length L_xy.

The narrow-scan 2017--2018 trigger efficiency for the decay of &gamma;_d in &mu;⁺&mu;^-. The trigger efficiency is shown for &gamma;_d with 0&lt;|&eta;|&lt;1.1 as function of the transverse momentum, in events where the &gamma;_d L_xy is below 6&nbsp;m.

Efficiency of the cosmic-ray tagger as function of the &gamma;_d transverse decay length. The efficiency is calculated accepting the &mu;DPJs for which the cosmic-ray tagger score is &gt; 0.2 for each associated MS-only track.

Efficiency of the cosmic-ray tagger as function of the &gamma;_d transverse momentum. The efficiency is calculated accepting the &mu;DPJs for which the cosmic-ray tagger score is &gt; 0.2 for each associated MS-only track.

Efficiency of the QCD tagger as function of the &gamma;_d transverse decay length. The efficiency is calculated accepting the caloDPJs for which the QCD tagger score is &gt; 0.5.

Efficiency of the QCD tagger as function of the &gamma;_d transverse momentum. The efficiency is calculated accepting the caloDPJs for which the QCD tagger score is &gt; 0.5.

The extrapolated acceptance times efficiencies as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the SR_2&mu;^ggF.

The extrapolated acceptance times efficiencies as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the SR_c+&mu;^ggF.

The extrapolated acceptance times efficiencies as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the SR_2c^ggF.

The extrapolated acceptance times efficiencies as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the SR_c^WH.

The extrapolated acceptance times efficiencies as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the SR_2c^WH.

The extrapolated acceptance times efficiencies as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the SR_c+&mu;^WH.

The extrapolated acceptance times efficiencies for SR_2&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a Higgs-like scalar with a mass of 800&nbsp;GeV. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_c+&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a Higgs-like scalar with a mass of 800&nbsp;GeV. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_2c;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;2&gamma;_d+X process and a Higgs-like scalar with a mass of 800&nbsp;GeV. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_2&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the HAHM H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the ggF channel.

The extrapolated acceptance times efficiencies for SR_c+&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the HAHM H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the ggF channel.

The extrapolated acceptance times efficiencies for SR_2c;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the HAHM H&rarr;&nbsp;2&gamma;_d+X process and a SM Higgs boson for the ggF channel.

The extrapolated acceptance times efficiencies for SR_2&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;4&gamma;_d+X process and a Higgs-like scalar with a mass of 800&nbsp;GeV. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_c+&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;4&gamma;_d+X process and a Higgs-like scalar with a mass of 800&nbsp;GeV. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_2c;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;4&gamma;_d+X process and a Higgs-like scalar with a mass of 800&nbsp;GeV. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_2&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;4&gamma;_d+X process and a SM Higgs boson. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_c+&mu;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;4&gamma;_d+X process and a SM Higgs boson. The coloured bands represent the MC statistical uncertainties.

The extrapolated acceptance times efficiencies for SR_2c;^ggF, as a function of the &gamma;_d mean proper lifetime c&tau; for the FRVZ pp &rarr; H&rarr;&nbsp;4&gamma;_d+X process and a SM Higgs boson. The coloured bands represent the MC statistical uncertainties.

Observed limits at the 95% CL on the branching ratio (B), obtained from the SR_2&mu;^ggF, for the process pp &rarr; H&rarr;&nbsp;4&gamma;_d+X, for different &gamma;_d masses and a 125 GeV Higgs boson. The limits are shown assuming an FRVZ signal model.

Observed limits at the 95% CL on the branching ratio (B), obtained from the SR_c+&mu;^ggF, for the process pp &rarr; H&rarr;&nbsp;4&gamma;_d+X, for different &gamma;_d masses and a 125 GeV Higgs boson. The limits are shown assuming an FRVZ signal model.

Observed limits at the 95% CL on the branching ratio (B), obtained from the SR_2c^ggF, for the process pp &rarr; H&rarr;&nbsp;4&gamma;_d+X, for different &gamma;_d masses and a 125 GeV Higgs boson. The limits are shown assuming an FRVZ signal model.

Observed limits at the 95% CL on the cross section, obtained from the SR_2&mu;^ggF, for the process pp &rarr; H&rarr;&nbsp;2&gamma;_d+X, for different &gamma;_d masses and a Higgs-like scalar with a mass of 800&nbsp;GeV. The limits are shown assuming an FRVZ signal model.

Observed limits at the 95% CL on the cross section, obtained from the SR_c+&mu;^ggF, for the process pp &rarr; H&rarr;&nbsp;2&gamma;_d+X, for different &gamma;_d masses and a Higgs-like scalar with a mass of 800&nbsp;GeV. The limits are shown assuming an FRVZ signal model.

Observed limits at the 95% CL on the cross section, obtained from the SR_2c^ggF, for the process pp &rarr; H&rarr;&nbsp;2&gamma;_d+X and ggF selection, for different &gamma;_d masses and a Higgs-like scalar with a mass of 800&nbsp;GeV. The limits are shown assuming an FRVZ signal model.

Observed limits at the 95% CL on the cross section for the process pp &rarr; H&rarr;&nbsp;4&gamma;_d+X and ggF selection, for different &gamma;_d masses and a Higgs-like scalar with a mass of 800&nbsp;GeV. The limits are shown for the 2&mu; search channel, assuming an FRVZ signal model.

Observed limits at the 95% CL on the cross section for the process pp &rarr; H&rarr;&nbsp;4&gamma;_d+X and ggF selection, for different &gamma;_d masses and a Higgs-like scalar with a mass of 800&nbsp;GeV. The limits are shown for the c+&mu; search channel, assuming an FRVZ signal model.

Observed limits at the 95% CL on the cross section for the process pp &rarr; H&rarr;&nbsp;4&gamma;_d+X and ggF selection, for different &gamma;_d masses and a Higgs-like scalar with a mass of 800&nbsp;GeV. The limits are shown for the 2c search channel, assuming an FRVZ signal model.