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CMS-PAS-SUS-16-034
Search for new physics in final states with two opposite-sign, same-flavor leptons, jets, and missing transverse momentum in pp collisions at $\sqrt{s}= $ 13 TeV
Abstract: A search is presented for physics beyond the standard model in final states with two opposite-sign, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 35.9 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}= $ 13 TeV collected with the CMS detector at the LHC in 2016. The analysis uses the invariant mass of the lepton pair, searching for a kinematic edge or a resonant-like excess compatible with the Z boson mass. The search for a kinematic edge targets strong production while the resonance search targets both strongly and electroweakly produced new physics. Both search modes use several event categories, based on observables related to the lepton pair and the hadronic system, in order to increase the sensitivity to new physics. A fit is also employed to search for a possible kinematic edge position in the strong, non-resonant search. The observations in all signal regions are consistent with the expectations from the standard model, and the results are interpreted in the context of simplified models of supersymmetry.
Figures & Tables Summary Additional Figures & Tables References CMS Publications
Additional information on efficiencies needed for reinterpretation of these results are available here.
Additional technical material for CMS speakers can be found here.
Figures

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Figure 1:
Diagrams for models with decays containing at least one dilepton pair stemming from a Z decay are shown. The gluino GMSB model targeted by the strong on-Z search is shown in the left. The right diagram shows the chargino-neutralino production model resulting in a final state with a Z boson, a W boson, and two LSPs. In the gluino GMSB model, $\tilde{\mathrm {G}}$ denotes the massless gravitino.

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Figure 1-a:
Diagram for the gluino GMSB model targeted by the strong on-Z search, where $\tilde{\mathrm {G}}$ denotes the massless gravitino.

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Figure 1-b:
The diagram shows the chargino-neutralino production model resulting in a final state with a Z boson, a W boson, and two LSPs.

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Figure 2:
A diagram showing a model in which bottom squarks are pair produced with subsequent decays that contain at least one dilepton pair. This model features a characteristic edge in the ${m_{\ell \ell }}$ spectrum given approximately by the mass difference of the ${{\tilde{\chi }^0_2}}$ and ${{\tilde{\chi }^0_1}} $.

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Figure 3:
The ${E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the strong on-Z signal regions with $ {N_{\text {b-jets}}} = $ 0 (left) and $ {N_{\text {b-jets}}} \geq $ 1 (right). The rows show SRA (top), SRB (middle), and SRC (bottom). The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 3-a:
The ${E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the strong on-Z signal regions with $ {N_{\text {b-jets}}} = $ 0 for SRA. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 3-b:
The ${E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the strong on-Z signal regions with $ {N_{\text {b-jets}}} \geq $ 1 for SRA. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 3-c:
The ${E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the strong on-Z signal regions with $ {N_{\text {b-jets}}} = $ 0 for SRB. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 3-d:
The ${E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the strong on-Z signal regions with $ {N_{\text {b-jets}}} \geq $ 1 for SRB. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 3-e:
The ${E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the strong on-Z signal regions with $ {N_{\text {b-jets}}} = $ 0 for SRC. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 3-f:
The ${E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the strong on-Z signal regions with $ {N_{\text {b-jets}}} \geq $ 1 for SRC. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 4:
The $ {E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the electroweak on-Z WZ/ZZ (left), and HZ (right) signal regions. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 4-a:
The $ {E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the electroweak on-Z WZ/ZZ signal region. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 4-b:
The $ {E_{\mathrm {T}}^{\text {miss}}} $ distribution is shown for data compared to the background prediction in the electroweak HZ signal region. The $ {E_{\mathrm {T}}^{\text {miss}}} $ template prediction for each signal region is normalized to the first bin of each distribution, and therefore the prediction agrees with the data by construction.

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Figure 5:
Results of the counting experiment of the edge search. For each signal region, the number of observed events, shown as black data points, is compared to the total background estimate, shown as a blue line with a blue uncertainty band. The non flavor symmetric background component from instrumental $E_{\text {T}}^{\text {miss}}$ is indicated as a green area while the non flavor symmetric background with neutrinos is shown as a violet area.

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Figure 6:
Fit of the dilepton mass distributions to the signal-plus-background hypothesis in the baseline signal region, projected on the same-flavor (left) and opposite-flavor (right) event samples. The fit shape is shown as a blue, solid line. The individual fit components are indicated by dashed lines. The flavor-symmetric (FS) background is shown with a black dashed line. The Drell-Yan (DY) background is displayed with a purple dashed line. The extracted signal component is displayed with a red dashed line.

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Figure 6-a:
Fit of the dilepton mass distributions to the signal-plus-background hypothesis in the baseline signal region, projected on the same-flavor event sample. The fit shape is shown as a blue, solid line. The individual fit components are indicated by dashed lines. The flavor-symmetric (FS) background is shown with a black dashed line. The Drell-Yan (DY) background is displayed with a purple dashed line. The extracted signal component is displayed with a red dashed line.

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Figure 6-b:
Fit of the dilepton mass distributions to the signal-plus-background hypothesis in the baseline signal region, projected on the opposite-flavor event sample. The fit shape is shown as a blue, solid line.

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Figure 7:
Cross section upper limits and exclusions contours at 95% CL obtained from the results of the on-Z search interpreted in the gluino GMSB model. The region to the left of the red dotted (black solid) line shows the masses which are excluded by the expected (observed) limit.

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Figure 8:
Cross section upper limits and exclusions contours at 95% CL obtained from the results of the on-Z search interpreted in the electroweak WZ model. The region to the left of the red dotted (black solid) line shows the masses which are excluded by the expected (observed) limit.

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Figure 9:
Cross section upper limits and exclusion contours at 95% CL obtained from the results of the edge search interpreted in the slepton-edge model. The region to the left of the red dotted (black solid) line shows the masses which are excluded by the expected (observed) limit.

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Figure 10:
The covariance (left) and correlation (right) matrices for the background predictions in the on-Z strong signal regions. Within each signal region, the individual $ {E_{\mathrm {T}}^{\text {miss}}} $ bins are shown in increasing order starting from 100 GeV.

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Figure 10-a:
The covariance matrix for the background predictions in the on-Z strong signal regions. Within each signal region, the individual $ {E_{\mathrm {T}}^{\text {miss}}} $ bins are shown in increasing order starting from 100 GeV.

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Figure 10-b:
The correlation matrix for the background predictions in the on-Z strong signal regions. Within each signal region, the individual $ {E_{\mathrm {T}}^{\text {miss}}} $ bins are shown in increasing order starting from 100 GeV.

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Figure 11:
The covariance (left) and correlation (right) matrices for the background predictions in the on-Z electroweak signal regions. Within each signal region, the individual $ {E_{\mathrm {T}}^{\text {miss}}} $ bins are shown in increasing order starting from 100 GeV.

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Figure 11-a:
The covariance matrix for the background predictions in the on-Z electroweak signal regions. Within each signal region, the individual $ {E_{\mathrm {T}}^{\text {miss}}} $ bins are shown in increasing order starting from 100 GeV.

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Figure 11-b:
The correlation matrix for the background predictions in the on-Z electroweak signal regions. Within each signal region, the individual $ {E_{\mathrm {T}}^{\text {miss}}} $ bins are shown in increasing order starting from 100 GeV.

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Figure 12:
The covariance (left) and correlation (right) matrices for the background predictions in the edge strong signal regions.

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Figure 12-a:
The correlation matrix for the background predictions in the edge strong signal regions.

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Figure 12-b:
The covariance matrix for the background predictions in the edge strong signal regions.
Tables

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Table 1:
Summary of all signal region selections.

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Table 2:
Predicted and observed event yields are shown for the strong on-Z signal regions, for each region and ${E_{\mathrm {T}}^{\text {miss}}} $ bin defined in Table 1. The uncertainties shown include both statistical and systematic errors.

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Table 3:
Predicted and observed event yields are shown for the electroweak on-Z signal regions, for each region and $ {E_{\mathrm {T}}^{\text {miss}}} $ bin defined in Table 1. The uncertainties shown include both statistical and systematic errors.

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Table 4:
Results of the edge-search counting experiment for event yields in the signal regions. The statistical and systematic uncertainties are added in quadrature.

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Table 5:
Results of the unbinned maximum likelihood fit for event yields in the signal region, including the DY and FS background components, along with the fitted signal contribution and edge position. The fitted value for $R_{\mathrm {SF/OF}}$ and the local and global signal significances are also given. The quoted uncertainties account for both statistical and systematic sources.

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Table 6:
Systematic uncertainties taken into account for the signal yields and their typical values.
Summary
A search for physics beyond the standard model has been presented in the opposite-sign, same-flavor lepton; jets; and $E_{\mathrm{T}}^{\text{miss}}$ final state using a data sample of pp collisions collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. Searches are performed for signals that either produce a kinematic edge in the dilepton invariant mass, or use dilepton systems whose invariant mass is compatible with the decay of a Z boson. Comparing the observation to estimates for SM backgrounds obtained from data control samples, and no statistically significant evidence for a signal has been observed.

The search for strongly produced new physics containing an on-shell Z boson is interpreted in a model of gauge-mediated supersymmetry breaking, where the Z bosons are produced in decay chains initiated through gluino pair production. Gluino masses below 1500-1770 GeV have been excluded, depending on the neutralino mass, extending the previous exclusion limits derived from the previous CMS publication by almost 500 GeV.

The electroweak on-Z search has been interpreted in a simplified model of chargino-neutralino production where the neutralino decays to a Z boson and the LSP, and the chargino decays to a W boson and the LSP. In this model, we probe chargino masses in the range 160-610 GeV.

The search for a kinematic edge in the ${m_{\ell\ell}} $ distribution is interpreted in a simplified model based on bottom squark pair production, where dilepton mass edges are produced in decay chains containing the two lightest neutralinos and a slepton, where the branching ratios have been fixed to produce the desired topology. Bottom squark masses below 980 to 1200 GeV have been excluded, depending on the ${{\tilde{\chi}^0_2}} $ mass. These limits extend previous exclusion limits by 400-600 GeV depending also on the ${{\tilde{\chi}^0_2}} $ mass.
Additional Figures

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Additional Figure 1:
PDFs for the four input variables to the likelihood discriminant: ${E_{\mathrm {T}}^{\text {miss}}}$ (a), di-lepton ${p_{\mathrm {T}}}$ (b), $|\Delta \phi |$ between the leptons (c), and $\Sigma m_{\ell \text {b}}$ (d) for data in the OF region.

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Additional Figure 1-a:
PDFs for one of the four input variables to the likelihood discriminant: ${E_{\mathrm {T}}^{\text {miss}}}$ for data in the OF region.

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Additional Figure 1-b:
PDFs for one of the four input variables to the likelihood discriminant: di-lepton ${p_{\mathrm {T}}}$ for data in the OF region.

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Additional Figure 1-c:
PDFs for one of the four input variables to the likelihood discriminant: $|\Delta \phi |$ between the leptons for data in the OF region.

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Additional Figure 1-d:
PDFs for one of the four input variables to the likelihood discriminant: $\Sigma m_{\ell \text {b}}$ for data in the OF region.

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Additional Figure 2:
Fitted shape for backgrounds containing a Z boson for dielectron events (a) and dimuon events (b). The fitted shape consists of an exponential (green) and a Breit-wigner convolved with a double-sided Crystal-Ball (red), whose sum (blue) describes the backgrounds containing a Z boson.

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Additional Figure 2-a:
Fitted shape for backgrounds containing a Z boson for dielectron events. The fitted shape consists of an exponential (green) and a Breit-wigner convolved with a double-sided Crystal-Ball (red), whose sum (blue) describes the backgrounds containing a Z boson.

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Additional Figure 2-b:
Fitted shape for backgrounds containing a Z boson for dimuon events. The fitted shape consists of an exponential (green) and a Breit-wigner convolved with a double-sided Crystal-Ball (red), whose sum (blue) describes the backgrounds containing a Z boson.

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Additional Figure 3:
Result of fit in signal region for same-flavor (a) and opposite-flavor (b) events for data evaluating the null hypothesis.

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Additional Figure 3-a:
Result of fit in signal region for same-flavor events for data evaluating the null hypothesis.

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Additional Figure 3-b:
Result of fit in signal region for opposite-flavor events for data evaluating the null hypothesis.

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Additional Figure 4:
${m_{\ell \ell }}$ distribution in the ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ like (a) and non ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ like (b) edge signal regions.The number of observed events, shown as black data points, is compared to the total background estimate, shown as a blue line with a blue uncertainty band. The non flavor symmetric background component from instrumental $E_{\text {T}}^{\text {miss}}$ is indicated as a green area while the non flavor symmetric background with neutrinos is shown as a violet area.

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Additional Figure 4-a:
${m_{\ell \ell }}$ distribution in the ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ like (a) and non ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ like (b) edge signal regions.The number of observed events, shown as black data points, is compared to the total background estimate, shown as a blue line with a blue uncertainty band. The non flavor symmetric background component from instrumental $E_{\text {T}}^{\text {miss}}$ is indicated as a green area while the non flavor symmetric background with neutrinos is shown as a violet area.

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Additional Figure 4-b:
${m_{\ell \ell }}$ distribution in the ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ like (a) and non ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ like (b) edge signal regions.The number of observed events, shown as black data points, is compared to the total background estimate, shown as a blue line with a blue uncertainty band. The non flavor symmetric background component from instrumental $E_{\text {T}}^{\text {miss}}$ is indicated as a green area while the non flavor symmetric background with neutrinos is shown as a violet area.

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Additional Figure 5:
Two-dimensional distribution of the observed significances in the slepton-edge signal model.
Additional Tables

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Additional Table 1:
Cut flow table for the edge signal model for a mass point at $m_{\tilde{b}}=$ 900 GeV and $m_{\tilde{\chi }_{2}^{0}}=$ 150 GeV. Expected dilepton events refers to luminosity$\times $cross section$\times $branching ratio.

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Additional Table 2:
Cut flow table for the edge signal model for a mass point at $m_{\tilde{b}}=$ 900 GeV and $m_{\tilde{\chi }_{2}^{0}}=$ 500 GeV. Expected dilepton events refers to luminosity$\times $cross section$\times $branching ratio.

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Additional Table 3:
Cut flow table for the edge signal model for a mass point at $m_{\tilde{b}}=$ 1000 GeV and $m_{\tilde{\chi }_{2}^{0}}=$ 300 GeV. Expected dilepton events refers to luminosity$\times $cross section$\times $branching ratio.

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Additional Table 4:
Cut flow table for the edge signal model for a mass point at $m_{\tilde{b}}=$ 1200 GeV and $m_{\tilde{\chi }_{2}^{0}}=$ 200 GeV. Expected dilepton events refers to luminosity$\times $cross section$\times $branching ratio.

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Additional Table 5:
Cut flow table for the edge signal model for a mass point at $m_{\tilde{b}}=$ 1200 GeV and $m_{\tilde{\chi }_{2}^{0}}=$ 1000 GeV. Expected dilepton events refers to luminosity$\times $cross section$\times $branching ratio.

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Additional Table 6:
Cut flow table for the strong on-Z signal region selections for the gluino GMSB signal model with the mass of the gluino and the $\tilde{\chi }_{1}^{0}$ equal to 1400 and 700 GeV, respectively. The theoretical cross section for this signal is 25.3 fb and at least one Z boson was required to decay leptonically, for a branching fraction of 0.192.

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Additional Table 7:
Cut flow table for the electroweak on-Z signal region selections for the WZ signal model with the mass of the chargino and the LSP equal to 550 and 200 GeV, respectively. The theoretical cross section for this signal is 30.2 fb and the Z boson was required to decay leptonically, for a branching fraction of 0.10.
The code for calculating the MT2 variable can be found here.
A macro for calculating the nll variable and the RooWorkSpace with the fitted pdfs used for the calculation is available here.
References
1 P. Ramond Dual theory for free fermions PRD 3 (1971) 2415
2 Y. A. Golfand and E. P. Likhtman Extension of the algebra of Poincare group generators and violation of P invariance JEPTL 13 (1971)323
3 A. Neveu and J. H. Schwarz Factorizable dual model of pions Nucl. Phys. B 31 (1971) 86
4 D. V. Volkov and V. P. Akulov Possible universal neutrino interaction JEPTL 16 (1972)438
5 J. Wess and B. Zumino A Lagrangian model invariant under supergauge transformations PLB 49 (1974) 52
6 J. Wess and B. Zumino Supergauge transformations in four dimensions Nucl. Phys. B 70 (1974) 39
7 P. Fayet Supergauge invariant extension of the Higgs mechanism and a model for the electron and its neutrino Nucl. Phys. B 90 (1975) 104
8 H. P. Nilles Supersymmetry, supergravity and particle physics Phys. Rep. 110 (1984) 1
9 G. R. Farrar and P. Fayet Phenomenology of the Production, Decay, and Detection of New Hadronic States Associated with Supersymmetry PLB 76 (1978) 575
10 G. Buras, Ellis and Nanopoulos Aspects of the grand unification of strong, weak and electromagnetic interactions Nuclear Physics B 135 (1978), no. 1, 66
11 Haber and Kane The search for supersymmetry: Probing physics beyond the standard model Physics Reports 117 (1985), no. 2, 75
12 CMS Collaboration Search for Physics Beyond the Standard Model in Events with Two Leptons, Jets, and Missing Transverse Momentum in pp Collisions at $ \sqrt{s} = $ 8 TeV JHEP 04 (2015) 124 CMS-SUS-14-014
1502.06031
13 CMS Collaboration Search for new physics in final states with two opposite-sign, same-flavor leptons, jets, and missing transverse momentum in pp collisions at $ \sqrt{s} $ = 13 TeV JHEP 12 (2016) 013 CMS-SUS-15-011
1607.00915
14 CMS Collaboration Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at$ \sqrt{s} = $ 7 TeV Physics Letters B 718 (2013), no. 3, 815 CMS-SUS-11-011
1206.3949
15 CMS Collaboration Search for physics beyond the standard model in opposite-sign dilepton events in pp collisions at$ \sqrt{s} = $ 7 TeV Journal of High Energy Physics 2011 (2011), no. 6, 26 CMS-SUS-10-007
1103.1348
16 CMS Collaboration Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV The European Physical Journal C 74 (2014), no. 9, 1 CMS-SUS-13-006
1405.7570
17 CMS Collaboration Searches for electroweak neutralino and chargino production in channels with Higgs, $ Z $, and $ W $ bosons in $ pp $ collisions at 8 TeV PRD 90 (Nov, 2014) 092007 CMS-SUS-14-002
1409.3168
18 ATLAS Collaboration Search for supersymmetry in events containing a same-flavour opposite-sign dilepton pair, jets, and large missing transverse momentum in $ \sqrt{s} = $ 8 TeV pp collisions with the ATLAS detector EPJC 75 (2015) 318, , [Erratum: \emphEur. Phys. J. C 75 (2015) 463] 1503.03290
19 ATLAS Collaboration Search for the electroweak production of supersymmetric particles in $ \sqrt{s} = $ 8 TeV $ pp $ collisions with the ATLAS detector PRD 93 (Mar, 2016) 052002 1509.07152
20 ATLAS Collaboration Search for new phenomena in events containing a same-flavour opposite-sign dilepton pair, jets, and large missing transverse momentum in $ \sqrt{s} = $ 13 TeV pp collisions with the ATLAS detector 1611.05791
21 I. Hinchliffe et al. Precision SUSY measurements at CERN LHC PRD 55 (1997) 5520 hep-ph/9610544
22 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004 CMS-00-001
23 CMS Collaboration Particle-Flow Event Reconstruction in CMS and Performance for Jets, Taus, and MET CDS
24 CMS Collaboration Commissioning of the Particle-flow Event Reconstruction with the first LHC collisions recorded in the CMS detector CDS
25 CMS Collaboration Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV JINST 10 (2015) P06005 CMS-EGM-13-001
1502.02701
26 CMS Collaboration Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV Journal of Instrumentation 10 (2015), no. 08, P08010
27 M. Cacciari, G. P. Salam, and G. Soyez The anti-$ k_t $ jet clustering algorithm JHEP 04 (2008) 063 0802.1189
28 M. Cacciari, G. P. Salam, and G. Soyez FastJet user manual EPJC 72 (2012) 1896 1111.6097
29 M. Cacciari and G. P. Salam Dispelling the N$ ^3 $ myth for the $ k_t $ jet-finder PLB 641 (2006) 57 hep-ph/0512210
30 CMS Collaboration Determination of Jet Energy Calibration and Transverse Momentum Resolution in CMS JINST 6 (2011) P11002 CMS-JME-10-011
1107.4277
31 M. Cacciari and G. P. Salam Pileup subtraction using jet areas PLB 659 (2008) 119 0707.1378
32 CMS Collaboration Identification of b quark jets at the CMS Experiment in the LHC Run 2 Technical Report CMS-PAS-BTV-15-001
33 J. Alwall et al. The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations JHEP 07 (2014) 079 1405.0301
34 S. Alioli, P. Nason, C. Oleari, and E. Re NLO single-top production matched with shower in POWHEG: s- and t-channel contributions JHEP 11 (2010) 111 0907.4076v2
35 E. Re Single-top Wt-channel production matched with parton showers using the POWHEG method EPJC 71 (2011) 1547 1009.2450
36 R. Gavin, Y. Li, F. Petriello, and S. Quackenbush FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order CPC 182 (2011) 2388--2403 1011.3540
37 R. Gavin, Y. Li, F. Petriello, and S. Quackenbush W Physics at the LHC with FEWZ 2.1 CPC 184 (2013) 208--214 1201.5896
38 M. Czakon and A. Mitov Top++: A Program for the Calculation of the Top-Pair Cross-Section at Hadron Colliders CPC 185 (2014) 2930 1112.5675
39 C. Borschensky et al. Squark and gluino production cross sections in pp collisions at $ \sqrt{s} = $ 13, 14, 33 and 100 TeV EPJC 74 (2014), no. 12 1407.5066
40 B. Fuks, M. Klasen, D. R. Lamprea, and M. Rothering Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV JHEP 10 (2012) 081 1207.2159
41 B. Fuks, M. Klasen, D. R. Lamprea, and M. Rothering Precision predictions for electroweak superpartner production at hadron colliders with Resummino EPJC 73 (2013) 2480 1304.0790
42 J. Alwall et al. The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations JHEP 07 (2014) 079 1405.0301
43 S. Frixione, P. Nason, and C. Oleari Matching NLO QCD computations with Parton Shower simulations: the POWHEG method JHEP 11 (2007) 070 0709.2092
44 T. Sjostrand, S. Mrenna, and P. Z. Skands A Brief Introduction to PYTHIA 8.1 CPC 178 (2008) 852--867 0710.3820
45 NNPDF Collaboration Parton distributions for the LHC Run II JHEP 04 (2015) 040 1410.8849
46 GEANT4 Collaboration GEANT4 --- a simulation toolkit NIMA 506 (2003) 250
47 S. Abdullin et al. The fast simulation of the CMS detector at LHC J. Phys. Conf. Ser. 331 (2011) 032049
48 K. T. Matchev and S. D. Thomas Higgs and Z boson signatures of supersymmetry PRD 62 (2000) 077702 hep-ph/9908482
49 P. Meade, M. Reece, and D. Shih Prompt decays of general neutralino NLSPs at the Tevatron JHEP 05 (2010) 105 0911.4130
50 J. T. Ruderman and D. Shih General neutralino NLSPs at the early LHC JHEP 08 (2012) 159 1103.6083
51 C. G. Lester and D. J. Summers Measuring masses of semiinvisibly decaying particles pair produced at hadron colliders PLB 463 (1999) 99 hep-ph/9906349
52 A. Barr, C. Lester, and P. Stephens A variable for measuring masses at hadron colliders when missing energy is expected; $ M_{T2} $ : the truth behind the glamour JPG 29 (2003) 2343 hep-ph/0304226
53 M. J. Oreglia PhD thesis, Stanford University, 1980 SLAC Report SLAC-R-236, see Appendix D
54 Olive et al. Review of Particle Physics CPC 38 (2014) 090001
55 T. Junk Confidence level computation for combining searches with small statistics NIMA 434 (1999) 435 hep-ex/9902006
56 A. L. Read Presentation of search results: the $ CL_s $ technique JPG 28 (2002) 2693
57 ATLAS and CMS Collaborations Procedure for the LHC Higgs boson search combination in summer 2011 CMS-NOTE-2011-005
58 G. Cowan, K. Cranmer, E. Gross, and O. Vitells Asymptotic formulae for likelihood-based tests of new physics EPJC 71 (2011) 1554 1007.1727
59 CMS Collaboration Simplified likelihood for the re-interpretation of public CMS results CDS
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