CERN Accelerating science

Feynman diagrams of the signal process considered, targeting pair production of electroweak sparticles decaying to two light SM fermions $x$ (including all leptons and quarks except top and bottom) and a \ninoone~particle, which then decays to either a $Z$ or Higgs boson along with a \gravino. Each of the \ninoone~particles is required to decay to a Higgs (Z) boson as shown on the left (right) which decays to a diphoton (dielectron) final state. The other \ninoone is not used in the analysis, and the Higgs/$Z$ boson decays with its Standard Model branching ratio.

Feynman diagrams of the signal process considered, targeting pair production of electroweak sparticles decaying to two light SM fermions $x$ (including all leptons and quarks except top and bottom) and a \ninoone~particle, which then decays to either a $Z$ or Higgs boson along with a \gravino. Each of the \ninoone~particles is required to decay to a Higgs (Z) boson as shown on the left (right) which decays to a diphoton (dielectron) final state. The other \ninoone is not used in the analysis, and the Higgs/$Z$ boson decays with its Standard Model branching ratio.

Illustration of the two-dimensional calo-vertexing procedure to calculate the \vr~and \vz~discriminating variables used in the analysis, with $R$ on the y-axis and $z$ on the x-axis. The three layers of the LAr calorimeter are highlighted, along with the energy deposits left by the passage of the two daughter photons $\gamma_1$ and $\gamma_2$ of the LLP. The location of the secondary vertex (SV) is determined by the pointing measurements of the two photons. \vr~is defined as the distance in R from the SV to the beamline, and \vz~as the distance in $z$ from the SV to the PV.

Distribution of leading versus subleading electron LAr timing values for a \Zee~analysis selection where at least two electrons are required that have 68 GeV $<$ m$_{ee}$ $<$ 108 GeV and $|\Delta\eta(e_1,e_2)| >$ 0.1. Populations of electrons from satellite collisions are visible at $\pm 5$~ns and +10~ns.

Distribution of the average timing (\tavg) for the expected background in the signal region, obtained by transforming data templates from the CR according to the background estimation procedure. Superimposed are the expected distributions for representative signal models in the SR, labeled by the \ninoone~mass (in \GeV) and lifetime (in ns), as well as the decay channel to $H$ or $Z$.

Resolution of the photon pointing variable \zorig as a function of \zorig in units of mm. Shown are prompt \Zee~data and simulation in a selection of events with at least two electrons that have 68 GeV $<$ m$_{ee}$ $<$ 108 GeV, and $|\Delta\eta(e_1,e_2)| >$ 0.1. Overlaid for comparison are representative signals in the SR selection, labeled by the \ninoone~mass in \GeV, the \ninoone~lifetime in ns, and the decay channel to $H$ or $Z$.

Distribution of the displacement $\rho$ for the expected background in the signal region, obtained by transforming data templates from the CR according to the background estimation procedure. Superimposed are the expected distributions for representative signal models in the SR, labeled by the \ninoone~mass (in \GeV) and lifetime (in ns), as well as the decay channel to $H$ or $Z$. Signals with an $H$ decay have a slightly broader distribution due to sculpting of the $\rho$ distribution by the lower bound of \myy~imposed at 60 GeV: larger displacement leads to a greater underestimation of the \myy~value, and as the $Z$ mass is lower than that of the $H$, the $Z$ signals are more affected.

Average timing distributions for VR($t$) data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories.

Average timing distributions for VR($t$) data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories.

Average timing distributions for VR($t$) data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories.

Average timing distributions for VR($t$) data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories.

Average timing distributions for VR($t$) data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories.

Average timing distributions for SR data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories. For comparison, the expected timing shapes for a few different signal models are superimposed, with each model labeled by the values of the \ninoone \ mass and lifetime, as well as decay mode. To provide some indication of the variations in signal yield and shape, three signal models are shown for each of the \ninoone \ decay modes, namely \ninoone~$\rightarrow$~\HG \ and \ninoone~$\rightarrow$~\ZG. The models shown include a rather low \ninoone \ mass value of 135~GeV for lifetimes of either 2~ns or 10~ns, and a higher \ninoone \ mass value which is near the 95\% CL exclusion limit for each decay mode for a lifetime of 2~ns. Each signal model is shown with the signal normalization corresponding to a BR value of unity for the decay mode in question.

Average timing distributions for SR data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories. For comparison, the expected timing shapes for a few different signal models are superimposed, with each model labeled by the values of the \ninoone \ mass and lifetime, as well as decay mode. To provide some indication of the variations in signal yield and shape, three signal models are shown for each of the \ninoone \ decay modes, namely \ninoone~$\rightarrow$~\HG \ and \ninoone~$\rightarrow$~\ZG. The models shown include a rather low \ninoone \ mass value of 135~GeV for lifetimes of either 2~ns or 10~ns, and a higher \ninoone \ mass value which is near the 95\% CL exclusion limit for each decay mode for a lifetime of 2~ns. Each signal model is shown with the signal normalization corresponding to a BR value of unity for the decay mode in question.

Average timing distributions for SR data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories. For comparison, the expected timing shapes for a few different signal models are superimposed, with each model labeled by the values of the \ninoone \ mass and lifetime, as well as decay mode. To provide some indication of the variations in signal yield and shape, three signal models are shown for each of the \ninoone \ decay modes, namely \ninoone~$\rightarrow$~\HG \ and \ninoone~$\rightarrow$~\ZG. The models shown include a rather low \ninoone \ mass value of 135~GeV for lifetimes of either 2~ns or 10~ns, and a higher \ninoone \ mass value which is near the 95\% CL exclusion limit for each decay mode for a lifetime of 2~ns. Each signal model is shown with the signal normalization corresponding to a BR value of unity for the decay mode in question.

Average timing distributions for SR data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories. For comparison, the expected timing shapes for a few different signal models are superimposed, with each model labeled by the values of the \ninoone \ mass and lifetime, as well as decay mode. To provide some indication of the variations in signal yield and shape, three signal models are shown for each of the \ninoone \ decay modes, namely \ninoone~$\rightarrow$~\HG \ and \ninoone~$\rightarrow$~\ZG. The models shown include a rather low \ninoone \ mass value of 135~GeV for lifetimes of either 2~ns or 10~ns, and a higher \ninoone \ mass value which is near the 95\% CL exclusion limit for each decay mode for a lifetime of 2~ns. Each signal model is shown with the signal normalization corresponding to a BR value of unity for the decay mode in question.

Average timing distributions for SR data and the estimated background as determined by the background-only fit, in each of the five exclusive $\rho$ categories. For comparison, the expected timing shapes for a few different signal models are superimposed, with each model labeled by the values of the \ninoone \ mass and lifetime, as well as decay mode. To provide some indication of the variations in signal yield and shape, three signal models are shown for each of the \ninoone \ decay modes, namely \ninoone~$\rightarrow$~\HG \ and \ninoone~$\rightarrow$~\ZG. The models shown include a rather low \ninoone \ mass value of 135~GeV for lifetimes of either 2~ns or 10~ns, and a higher \ninoone \ mass value which is near the 95\% CL exclusion limit for each decay mode for a lifetime of 2~ns. Each signal model is shown with the signal normalization corresponding to a BR value of unity for the decay mode in question.

The 95\% CL limits on $\sigma(pp \rightarrow \ninoone \ninoone$) in fb as a function of \ninoone~mass (left) and \ninoone~lifetime (right), for the different decay modes of $\mathcal{B}$(\ninoone $\rightarrow H + \tilde{G}$) = 1 (top) and $\mathcal{B}$(\ninoone $\rightarrow Z +\tilde{G}$) = 1 (bottom). For the limits as a function of mass (lifetime), several signal models with varying lifetime (mass) are overlaid for comparison. Included are the theoretical expectations from higgsino production for each mass hypothesis, calculated from a GMSB SUSY model that assumes nearly degenerate \ninoone, \cinoone, and \ninotwo.

The 95\% CL limits on $\sigma(pp \rightarrow \ninoone \ninoone$) in fb as a function of \ninoone~mass (left) and \ninoone~lifetime (right), for the different decay modes of $\mathcal{B}$(\ninoone $\rightarrow H + \tilde{G}$) = 1 (top) and $\mathcal{B}$(\ninoone $\rightarrow Z +\tilde{G}$) = 1 (bottom). For the limits as a function of mass (lifetime), several signal models with varying lifetime (mass) are overlaid for comparison. Included are the theoretical expectations from higgsino production for each mass hypothesis, calculated from a GMSB SUSY model that assumes nearly degenerate \ninoone, \cinoone, and \ninotwo.

The 95\% CL limits on $\sigma(pp \rightarrow \ninoone \ninoone$) in fb as a function of \ninoone~mass (left) and \ninoone~lifetime (right), for the different decay modes of $\mathcal{B}$(\ninoone $\rightarrow H + \tilde{G}$) = 1 (top) and $\mathcal{B}$(\ninoone $\rightarrow Z +\tilde{G}$) = 1 (bottom). For the limits as a function of mass (lifetime), several signal models with varying lifetime (mass) are overlaid for comparison. Included are the theoretical expectations from higgsino production for each mass hypothesis, calculated from a GMSB SUSY model that assumes nearly degenerate \ninoone, \cinoone, and \ninotwo.

The 95\% CL limits on $\sigma(pp \rightarrow \ninoone \ninoone$) in fb as a function of \ninoone~mass (left) and \ninoone~lifetime (right), for the different decay modes of $\mathcal{B}$(\ninoone $\rightarrow H + \tilde{G}$) = 1 (top) and $\mathcal{B}$(\ninoone $\rightarrow Z +\tilde{G}$) = 1 (bottom). For the limits as a function of mass (lifetime), several signal models with varying lifetime (mass) are overlaid for comparison. Included are the theoretical expectations from higgsino production for each mass hypothesis, calculated from a GMSB SUSY model that assumes nearly degenerate \ninoone, \cinoone, and \ninotwo.

The 95\% CL exclusion limits on the target signal hypothesis, for \ninoone~lifetime in ns as a function of \ninoone~mass in GeV. The overlaid curves correspond to different decay hypotheses, where the assumed cross-section is for higgsino production, and the \ninoone~decays to $H + \tilde{G}$ or $Z + \tilde{G}$ such that $\mathcal{B}(H + \tilde{G}) + \mathcal{B}(Z + \tilde{G})$ = 100\%. The curve shown in red represents the decay hypothesis where the \ninoone~decays to $Z + \tilde{G}$ with 100\% branching ratio. The curve shown in blue represents the decay hypothesis where the \ninoone~decays to $H + \tilde{G}$ with 100\% branching ratio.

The 95\% CL limits on $\sigma(pp \rightarrow \ninoone \ninoone$) in fb as a function of $\ninoone$ branching ratio to the SM Higgs boson, where the assumed cross-section is for higgsino production, and $\mathcal{B}$(\ninoone $\rightarrow Z +\tilde{G}$) = 1 - $\mathcal{B}$(\ninoone $\rightarrow H + \tilde{G}$). Several signal hypotheses are overlaid that are labelled by the \ninoone~mass, all with a fixed \ninoone~lifetime of 2 ns. Included are the theoretical expectations for each mass hypothesis, calculated from a GMSB SUSY model that assumes nearly degenerate \ninoone, \cinoone, and \ninotwo.