Single Event Sensitivity (SES) for the $K^{+}\rightarrow\pi^{+}X$ search as a function of X mass.

Model-independent constraints on the branching ratio of the $K^{+}\rightarrow\pi^{+}X$ decay

Model-independent constraints on the branching ratio of the $K^{+}\rightarrow\pi^{+}X$ decay

Observed model-independent upper limits at 90 % CL of $\mathcal{B}(K^{+}\rightarrow\pi^{+}X)$ as function of $X$ mass, for several $X$ lifetime hypotheses, assuming $X$ decays to visible SM particles.

Observed model-independent upper limits at 90 % CL of $\mathcal{B}(K^{+}\rightarrow\pi^{+}X)$ as function of $X$ mass, for several $X$ lifetime hypotheses, assuming $X$ decays to visible SM particles.

Di-muon mass spectrum of selected $K^{+}\rightarrow\pi^{+}\mu^{+}\mu^{-}$ events from 2017–2018 data.

Di-muon mass spectrum of selected $K^{+}\rightarrow\pi^{+}\mu^{+}\mu^{-}$ events from 2017–2018 data.

Expected and observed model-independent upper limits at 90 % CL for $\mathcal{B}(K^{+}\rightarrow\pi^{+}X)\times\mathcal{B}(X\rightarrow\mu^{+}\mu^{-})$ as a function of $m_{X}$ for $\tau_{X}=0$.

Expected and observed model-independent upper limits at 90 % CL for $\mathcal{B}(K^{+}\rightarrow\pi^{+}X)\times\mathcal{B}(X\rightarrow\mu^{+}\mu^{-})$ as a function of $m_{X}$ for $\tau_{X}=0$.

Observed model-independent upper limits at 90 % CL for $\mathcal{B}(K^{+}\rightarrow\pi^{+}X)\times\mathcal{B}(X\rightarrow\mu^{+}\mu^{-})$ for several $\tau_{X}$ values.

Observed model-independent upper limits at 90 % CL for $\mathcal{B}(K^{+}\rightarrow\pi^{+}X)\times\mathcal{B}(X\rightarrow\mu^{+}\mu^{-})$ for several $\tau_{X}$ values.

Branching ratio of the $K^{+}\rightarrow\pi^{+}A^{\prime}$ decay divided by the kinetic mixing coupling squared, $\varepsilon^{2}$, as a function of $m_{A^{\prime}}$ for the BC2 model with dark photon $A^{\prime}$.

Branching ratio of the $K^{+}\rightarrow\pi^{+}A^{\prime}$ decay divided by the kinetic mixing coupling squared, $\varepsilon^{2}$, as a function of $m_{A^{\prime}}$ for the BC2 model with dark photon $A^{\prime}$.

Excluded region, at 90 % CL, of the parameter space $(m_{A^{\prime}},\varepsilon)$ for a dark photon $A^{\prime}$, decaying invisibly, in the BC2 model for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded region, at 90 % CL, of the parameter space $(m_{A^{\prime}},\varepsilon)$ for a dark photon $A^{\prime}$, decaying invisibly, in the BC2 model for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded region, at 90 % CL, of the parameter space $(m_{A^{\prime}},\varepsilon)$ for a dark photon $A^{\prime}$, decaying invisibly, in the BC2 model for the NA62 $\pi^{0}\rightarrow{\rm inv}$ search.

Excluded region, at 90 % CL, of the parameter space $(m_{A^{\prime}},\varepsilon)$ for a dark photon $A^{\prime}$, decaying invisibly, in the BC2 model for the NA62 $\pi^{0}\rightarrow{\rm inv}$ search.

Branching ratio of the $K^{+}\rightarrow\pi^{+}S$ decay divided by $\text{sin}^{2}\theta$, as a function of $m_{S}$.

Branching ratio of the $K^{+}\rightarrow\pi^{+}S$ decay divided by $\text{sin}^{2}\theta$, as a function of $m_{S}$.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta)$ for a dark scalar $S$, in the BC4-inv model for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta)$ for a dark scalar $S$, in the BC4-inv model for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta)$ for a dark scalar $S$, in the BC4-inv model for the NA62 $\pi^{0}\rightarrow{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta)$ for a dark scalar $S$, in the BC4-inv model for the NA62 $\pi^{0}\rightarrow{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta$) for a dar scalar S, in the BC4 model, from the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta$) for a dar scalar S, in the BC4 model, from the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta$) for a dar scalar S, in the BC4 model, from the NA62 $K^{+}\rightarrow\pi^{+}\mu^{+}\mu^{-}$ study.

Excluded regions, at 90 % CL, of the parameter space $(m_{S},\rm{sin}^{2}\theta$) for a dar scalar S, in the BC4 model, from the NA62 $K^{+}\rightarrow\pi^{+}\mu^{+}\mu^{-}$ study.

Branching ratio of the $K^{+}\rightarrow\pi^{+}a$ decay divided by $(C_{ff}/\Lambda)^{2}$, as a function of $m_{a}$, assuming Λ = 1 TeV.

Branching ratio of the $K^{+}\rightarrow\pi^{+}a$ decay divided by $(C_{ff}/\Lambda)^{2}$, as a function of $m_{a}$, assuming Λ = 1 TeV.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\Lambda)$ for an ALP $a$, in the BC10-inv model, evaluated assuming $\Lambda = 1$ TeV, for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\Lambda)$ for an ALP $a$, in the BC10-inv model, evaluated assuming $\Lambda = 1$ TeV, for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\Lambda)$ for an ALP $a$, in the BC10-inv model, evaluated assuming $\Lambda = 1$ TeV, for the NA62 $\pi^{0}\rightarrow\rm{inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\Lambda)$ for an ALP $a$, in the BC10-inv model, evaluated assuming $\Lambda = 1$ TeV, for the NA62 $\pi^{0}\rightarrow\rm{inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\lambda)$ for an ALP $a$, in the BC10 model, evaluated assuming $\Lambda = 1$ TeV for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\lambda)$ for an ALP $a$, in the BC10 model, evaluated assuming $\Lambda = 1$ TeV for the NA62 $K^{+}\rightarrow\pi^{+}X_{\rm inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\lambda)$ for an ALP $a$, in the BC10 model, evaluated assuming $\Lambda = 1$ TeV for the NA62 $\pi^{0}\rightarrow\rm{inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\lambda)$ for an ALP $a$, in the BC10 model, evaluated assuming $\Lambda = 1$ TeV for the NA62 $\pi^{0}\rightarrow\rm{inv}$ search.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\lambda)$ for an ALP $a$, in the BC10 model, evaluated assuming $\Lambda = 1$ TeV for the NA62 $K^{+}\rightarrow\pi^{+}\mu^{+}\mu^{-}$ study.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{ff}/\lambda)$ for an ALP $a$, in the BC10 model, evaluated assuming $\Lambda = 1$ TeV for the NA62 $K^{+}\rightarrow\pi^{+}\mu^{+}\mu^{-}$ study.

Branching ratio of the $K^{+}\rightarrow\pi^{+}a$ decay divided by $(C_{GG}/\Lambda)^{2}$, as a function of $m_{a}$, assuming $\Lambda = 1$ TeV.

Branching ratio of the $K^{+}\rightarrow\pi^{+}a$ decay divided by $(C_{GG}/\Lambda)^{2}$, as a function of $m_{a}$, assuming $\Lambda = 1$ TeV.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{GG}/\Lambda)$ for an ALP $a$, of the BC11 model, evaluated assuming $\Lambda = 1$ TeV, from the NA62 search for $K^{+}\rightarrow\pi^{+}X_{\rm inv}$.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{GG}/\Lambda)$ for an ALP $a$, of the BC11 model, evaluated assuming $\Lambda = 1$ TeV, from the NA62 search for $K^{+}\rightarrow\pi^{+}X_{\rm inv}$.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{GG}/\Lambda)$ for an ALP $a$, of the BC11 model, evaluated assuming $\Lambda = 1$ TeV, from the NA62 search for $\pi^{0}\rightarrow\rm{inv}$.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{GG}/\Lambda)$ for an ALP $a$, of the BC11 model, evaluated assuming $\Lambda = 1$ TeV, from the NA62 search for $\pi^{0}\rightarrow\rm{inv}$.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{GG}/\Lambda)$ for an ALP $a$, of the BC11 model, evaluated assuming $\Lambda = 1$ TeV, from the NA62 $K^{+}\rightarrow\pi^{+}\gamma\gamma$ study.

Excluded regions, at 90 % CL, of the parameter space $(m_{a}, C_{GG}/\Lambda)$ for an ALP $a$, of the BC11 model, evaluated assuming $\Lambda = 1$ TeV, from the NA62 $K^{+}\rightarrow\pi^{+}\gamma\gamma$ study.

Correlation matrix for the correlated systematic uncertainties of the forward rapidity $\eta$ meson cross section.

Correlation matrix for the correlated systematic uncertainties of the central rapidity $\eta$ meson cross section.

The invariant yields of $\phi$ and $\omega+\rho$ mesons as a function of $\langle N_{\rm part}\rangle$ in Au+Au collisions. The systematic uncertainties of type-A (uncorrelated) are combined with statistical uncertainties in quadrature and are labeled as stat. Type-B (correlated) systematic uncertainties are listed as sys.

$R_{AA}$ of $\phi$ meson as a function of $p_T$ for in Au+Au collisions at $\sqrt{s_{_{NN}}}=200$~GeV, compared with Cu+Au collisions at $1.2<|y|<2.2$. The systematic uncertainties of type-A (uncorrelated) are combined with statistical uncertainties in quadrature and are labeled as stat. Type-B (correlated) systematic uncertainties are listed as sys.

$R_{AA}$ of $\phi$ meson as a function of $\langle N_{\rm part}\rangle$ for $1.2<|y|<2.2$ in Au+Au collisions at $\sqrt{s_{_{NN}}}=200$~GeV. The systematic uncertainties of type-A (uncorrelated) are combined with statistical uncertainties in quadrature and are labeled as stat. Type-B (correlated) systematic uncertainties are listed as sys.

$\xi$ distributions for different jet $p_T$ bins.

$\xi$ distributions for different jet $p_T$ bins.

The $j_T/p_{T}^{\rm jet}$ distributions for different jet $p_T$ bins.

The $j_T/p_{T}^{\rm jet}$ distributions for different jet $p_T$ bins.

$r$ distributions for different jet $p_T$ bins.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T}}^{\mathrm{lead.\,lep.}}$.

Fiducial differential cross-sections as a function of $p_{\mathrm{T}}^{\mathrm{sub-lead.\,lep.}}$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T}}^{\mathrm{sub-lead.\,lep.}}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T}}^{\mathrm{sub-lead.\,lep.}}$.

Fiducial differential cross-sections as a function of $p_{\mathrm{T},e\mu}$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$.

Fiducial differential cross-sections as a function of $|y_{e\mu}|$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$.

Fiducial differential cross-sections as a function of $m_{e\mu}$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $m_{e\mu}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $m_{e\mu}$.

Fiducial differential cross-sections as a function of $|\Delta\phi_{e\mu}|$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $|\Delta\phi_{e\mu}|$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $|\Delta\phi_{e\mu}|$.

Fiducial differential cross-sections as a function of $\cos(\theta^{*})$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $\cos(\theta^{*})$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $\cos(\theta^{*})$.

Fiducial differential cross-sections as a function of $E_{\mathrm{T}}^{\mathrm{miss}}$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $E_{\mathrm{T}}^{\mathrm{miss}}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $E_{\mathrm{T}}^{\mathrm{miss}}$.

Fiducial differential cross-sections as a function of $H_{\mathrm{T}}^{\mathrm{lep}+\mathrm{MET}}$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $H_{\mathrm{T}}^{\mathrm{lep}+\mathrm{MET}}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $H_{\mathrm{T}}^{\mathrm{lep}+\mathrm{MET}}$.

Fiducial differential cross-sections as a function of $m_{\mathrm{T},e\mu}$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $m_{\mathrm{T},e\mu}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $m_{\mathrm{T},e\mu}$.

Fiducial differential cross-sections as a function of the number of jets. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable Number of jets ($p_{\mathrm{T}} > $ 30 GeV).

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable Number of jets ($p_{\mathrm{T}} > $ 30 GeV).

Fiducial differential cross-sections as a function of $S_{\mathrm{T}}$. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The results are compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1, with the NNLO + PS predictions from Powheg MiNNLO + Pythia8 and Geneva + Pythia8, as well as Sherpa2.2.12 NLO + PS predictions. The last three predictions are combined with Sherpa 2.2.2 for the $gg$ initial state and Sherpa 2.2.12 for electroweak $WWjj$ production. These contributions are modelled at LO but a NLO QCD $k$-factor of 1.7 is applied for gluon induced production. Theoretical predictions are indicated as markers with vertical lines denoting PDF, scale and parton shower uncertainties. Markers are staggered for better visibility.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $S_{\mathrm{T}}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $S_{\mathrm{T}}$.

Fiducial differential cross-sections for $p_{\mathrm{T},e\mu}$ in the region with 85 $<m_{e\mu}<$ 150, for the nNNLO MATRIX prediction and various four flavour PDF sets. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The measurement is compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1 using four different four-flavour NNLO PDF sets: NNPDF3.0, NNPDF3.1, CT18, and MSHT20.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$ (85 $<m_{e\mu}<$ 150).

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$ (85 $<m_{e\mu}<$ 150).

Fiducial differential cross-sections for $|y_{e\mu}|$ in the region with 85 $<m_{e\mu}<$ 150, for the nNNLO MATRIX prediction and various four flavour PDF sets. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The measurement is compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1 using four different four-flavour NNLO PDF sets: NNPDF3.0, NNPDF3.1, CT18, and MSHT20.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$ (85 $<m_{e\mu}<$ 150).

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$ (85 $<m_{e\mu}<$ 150).

Fiducial differential cross-sections for $p_{\mathrm{T},e\mu}$ in the region with 150 $<m_{e\mu}<$ 250, for the nNNLO MATRIX prediction and various four flavour PDF sets. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The measurement is compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1 using four different four-flavour NNLO PDF sets: NNPDF3.0, NNPDF3.1, CT18, and MSHT20.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$ (150 $<m_{e\mu}<$ 250).

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$ (150 $<m_{e\mu}<$ 250).

Fiducial differential cross-sections for $|y_{e\mu}|$ in the region with 150 $<m_{e\mu}<$ 250, for the nNNLO MATRIX prediction and various four flavour PDF sets. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The measurement is compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1 using four different four-flavour NNLO PDF sets: NNPDF3.0, NNPDF3.1, CT18, and MSHT20.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$ (150 $<m_{e\mu}<$ 250).

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$ (150 $<m_{e\mu}<$ 250).

Fiducial differential cross-sections for $p_{\mathrm{T},e\mu}$ in the region with $m_{e\mu}>$ 250, for the nNNLO MATRIX prediction and various four flavour PDF sets. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The right-hand-side axis indicates the integrated cross-section of the rightmost bin. The measurement is compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1 using four different four-flavour NNLO PDF sets: NNPDF3.0, NNPDF3.1, CT18, and MSHT20.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$ ($m_{e\mu}>$ 250).

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T},e\mu}$ ($m_{e\mu}>$ 250).

Fiducial differential cross-sections for $|y_{e\mu}|$ in the region with $m_{e\mu}>$ 250, for the nNNLO MATRIX prediction and various four flavour PDF sets. The measured cross-section values are shown as points with error bars giving the statistical uncertainty and solid bands indicating the size of the total uncertainty. The measurement is compared to fixed-order nNNLO QCD + NLO EW predictions of Matrix 2.1 using four different four-flavour NNLO PDF sets: NNPDF3.0, NNPDF3.1, CT18, and MSHT20.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$ ($m_{e\mu}>$ 250).

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $|y_{e\mu}|$ ($m_{e\mu}>$ 250).

Measured value of the charge asymmetry, $A_{C}$.

Charge asymmetry $A_C$ measured as a function of the absolute difference of the absolute lepton rapidities $||\eta_{l+}|-|\eta_{l-}||$. The measured values are shown as points, whose error bars represent the statistical uncertainty, while the solid bands indicate the size of the total uncertainty. In the bottom panel, the central value of the charge asymmetry divided by the total uncertainty of the $A_C$ measurement is shown. The measurement is compared with the NNLO+PS predictions from Powheg MiNNLO+Pythia8 with vertical lines denoting PDF uncertainties.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $A_{C}$ vs. $||\eta_{l+}|-|\eta_{l-}||$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $A_{C}$ vs. $||\eta_{l+}|-|\eta_{l-}||$.

Charge asymmetry $A_C$ measured as a function of the invariant mass of the dilepton system $m_{e\mu}$. The measured values are shown as points, whose error bars represent the statistical uncertainty, while the solid bands indicate the size of the total uncertainty. In the bottom panel, the central value of the charge asymmetry divided by the total uncertainty of the $A_C$ measurement is shown. The measurement is compared with the NNLO+PS predictions from Powheg MiNNLO+Pythia8 with vertical lines denoting PDF uncertainties.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $A_{C}$ vs. $m_{e\mu}$.

Correlation matrix of the total uncertainties in the measured fiducial cross section for the observable $A_{C}$ vs. $m_{e\mu}$.

Measured value of the asymmetry in the CP-odd observable $O_{z}$, $A_{CP}$.

The extracted kinetic decoupling temperature is derived from $\pi^{-}$–d correlation functions.

This is the mixed event distribution for $\pi^{+}$–d, required for the fitting

This is the mixed event distribution for $\pi^{-}$–d, required for the fitting

The momentum smearing matrix, required for the fitting, used both for $\pi^{-}$–d and $\pi^{+}$–d

Pre-fit MC statistical uncertainties per bin. These values are used to quantify the MC statistical uncertainty contributions to the total uncertainty in $m_t$ based on elements from the covariance matrix obtained in the profile likelihood fit. Each MC statistical contribution is estimated by dividing the relevant covariance matrix entry (see Table 2) by the corresponding pre-fit MC statistical uncertainty for that bin.

The contribution of each source of systematic uncertainty to the total uncertainty in $m_t$ is provided. Each source's contribution is taken directly from the relevant element of the covariance matrix for the profile likelihood fit to $\overline{m_J}$, $m_{jj}$, and $m_{tj}$ using data. The sign of the effect of each uncertainty is included.

The fitted $m_t$ is provided for each replica generated using bootstrapping. Each replica is a 3D histogram of $m_{J}$, $m_{jj}$, and $m_{tj}$, where $m_{J}$ has 50 bins between 145.0 GeV and 205.0 GeV. This method uses the BootstrapGenerator class in ROOT to initialise a pseudo-random number generator for each event, which is seeded by the value of the eventNumber and runNumber variables for a given event in the input dataset. The pseudo-random numbers are drawn from a Poisson distribution with rate parameter equal to 1. These are used to fluctuate the amount by which each replica histogram is filled. There are 1000 replicas, numbered from 0 to 999.

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.

Total invariant mass distribution $m_{4\ell}$ in Signal Region 2.

Selected events in the ($m_{4\ell}$, $\left\langle m_{\ell\ell}\right\rangle$) plane, SR1

Selected events in the ($m_{4\ell}$, $\left\langle m_{\ell\ell}\right\rangle$) plane, SR2

Expected background events in the $(m_{4\ell}, \langle m_{\ell\ell}\rangle)$ plane, SR1

Expected signal shape for $(m_{S}, m_{Z_d}) = (110~\text{GeV},30~\text{GeV}$) in the $(m_{4\ell}, \langle m_{\ell\ell}\rangle)$ plane, SR1. The signal distributions are normalized to unit volume.

Expected background events in the $(m_{4\ell}, \langle m_{\ell\ell}\rangle)$ plane, SR2. Events that satisfy $|m_{ab,cd} - m_Z| < 8~\text{GeV}$ are removed by the Z-veto requirement, however not all events lying behind the mask in the plot, corresponding to $\langle m_{\ell\ell}\rangle$ values between 83 and 99 GeV, are deleted.

Expected signal shape for $(m_{S}, m_{Z_{d}}) = (750~\text{GeV},150~\text{GeV}$) in the $(m_{4\ell}, \langle m_{\ell\ell}\rangle)$ plane, SR2. The signal distributions are normalized to unit volume. Events that satisfy $|m_{ab,cd} - m_Z| < 8~\text{GeV}$ are removed by the Z-veto requirement, however not all events lying behind the mask in the plot, corresponding to $\langle m_{\ell\ell}\rangle$ values between 83 and 99 GeV, are deleted.

Expected 95% CL limit on $\sigma \mathcal{B}(S\rightarrow Z_{d}Z_{d} \rightarrow 4\ell)$, SR1

Observed 95% CL limit on $\sigma \mathcal{B}(S\rightarrow Z_{d}Z_{d} \rightarrow 4\ell)$, SR1

Observed / Expected 95% CL limit ratio in SR1

Expected 95% CL limit on $\mathcal{B}(S\rightarrow Z_{d}Z_{d} \rightarrow 4\ell)$ with Z-veto, SR2

Observed 95% CL limit on $\sigma \mathcal{B}(S\rightarrow Z_{d}Z_{d} \rightarrow 4\ell)$ with Z-veto, SR2

Observed / Expected 95% CL limit ratio with Z-veto, SR2

Local $p_0$-values in the ($m_{S}, m_{Z_{d}}$) plane, SR1

Local $p_0$-values in the ($m_{S}, m_{Z_{d}}$) plane, SR2 with Z-veto applied

Observed data in Signal Region 1 in the $(m_{4\ell}, \langle m_{\ell\ell}\rangle)$ plane.

Observed data in Signal Region 2 in the $(m_{4\ell}, \langle m_{\ell\ell}\rangle)$ plane. Events that satisfy $|m_{ab,cd} - m_Z| < 8~\text{GeV}$ are removed by the Z-veto requirement, however not all events lying behind the mask in the plot, corresponding to <m_ll> values between 83 and 99 GeV, are deleted.

Distributions of the average dilepton mass $\left\langle m_{\ell\ell}\right\rangle = \frac{1}{2}\left(m_{ab} + m_{cd}\right)$ for Signal Region 1 in the $4e$ final state.

Distributions of the average dilepton mass $\left\langle m_{\ell\ell}\right\rangle = \frac{1}{2}\left(m_{ab} + m_{cd}\right)$ for Signal Region 1 in the $2e2\mu$ final state.

Distributions of the average dilepton mass $\left\langle m_{\ell\ell}\right\rangle = \frac{1}{2}\left(m_{ab} + m_{cd}\right)$ for Signal Region 1 in the $4\mu$ final state.

Distributions of the average dilepton mass $\left\langle m_{\ell\ell}\right\rangle = \frac{1}{2}\left(m_{ab} + m_{cd}\right)$ for Signal Region 2 in the $4e$ final state.

Distributions of the average dilepton mass $\left\langle m_{\ell\ell}\right\rangle = \frac{1}{2}\left(m_{ab} + m_{cd}\right)$ for Signal Region 2 in the $2e2\mu$ final state.

Distributions of the average dilepton mass $\left\langle m_{\ell\ell}\right\rangle = \frac{1}{2}\left(m_{ab} + m_{cd}\right)$ for Signal Region 2 in the $4\mu$ final state.

Distributions of the total invariant mass $m_{4\ell}$ for Signal Region 1 in the $4e$ final state. The SR1 requirement $m_{4\ell} < 115~\text{GeV}$ is not applied here.

Distributions of the total invariant mass $m_{4\ell}$ for Signal Region 1 in the $2e2\mu$ final state. The SR1 requirement $m_{4\ell} < 115~\text{GeV}$ is not applied here.

Distributions of the total invariant mass $m_{4\ell}$ for Signal Region 1 in the $4\mu$ final state. The SR1 requirement $m_{4\ell} < 115~\text{GeV}$ is not applied here.

Distributions of the total invariant mass $m_{4\ell}$ for Signal Region 2 in the $4e$ final state.

Distributions of the total invariant mass $m_{4\ell}$ for Signal Region 2 in the $2e2\mu$ final state.

Distributions of the total invariant mass $m_{4\ell}$ for Signal Region 2 in the $4\mu$ final state.