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CMS-SUS-19-013 ; CERN-EP-2020-149

Search for supersymmetry in proton-proton collisions at $\sqrt{s} = $ 13 TeV in events with high-momentum Z bosons and missing transverse momentum

CMS Collaboration

10 August 2020

JHEP 09 (2020) 149

Abstract: A search for new physics in events with two highly Lorentz-boosted Z bosons and large missing transverse momentum is presented. The analyzed proton-proton collision data, corresponding to an integrated luminosity of 137 fb$^{-1}$, were recorded at $\sqrt{s} = $ 13 TeV by the CMS experiment at the CERN LHC. The search utilizes the substructure of jets with large radius to identify quark pairs from Z boson decays. Backgrounds from standard model processes are suppressed by requirements on the jet mass and the missing transverse momentum. No significant excess in the event yield is observed beyond the number of background events expected from the standard model. For a simplified supersymmetric model in which the Z bosons arise from the decay of gluinos, an exclusion limit of 1920 GeV on the gluino mass is set at 95% confidence level. This is the first search for beyond-standard-model production of pairs of boosted Z bosons plus large missing transverse momentum.

Links: e-print arXiv:2008.04422 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ;

Figures
png pdf	Figure 1: Signal diagram for the T5ZZ simplified model process. The assumed small mass splitting between the ${\mathrm{\tilde{g}}}$ and $\tilde{\chi}^{0}_{2}$ implies a massive $\tilde{\chi}^{0}_{2}$. We further assume a 100% branching fraction for the $\tilde{\chi}^{0}_{2}$ decay to the Z boson and $\tilde{\chi}^{0}_{1}$, leading to an energetic Z boson and large ${{p_{\mathrm {T}}} ^\text {miss}}$.
png pdf	Figure 2: Distributions of ${{p_{\mathrm {T}}} ^\text {miss}}$ for simulated SM backgrounds (stacked histograms), with only the hadronic baseline selection (left), and after the additional Z candidate selection (right). Expected signal contributions for two example mass points (dotted lines) are also shown. The last bin includes the overflow events.
png pdf	Figure 2-a: Distribution of ${{p_{\mathrm {T}}} ^\text {miss}}$ for simulated SM backgrounds (stacked histograms), with the hadronic baseline selection. Expected signal contributions for two example mass points (dotted lines) are also shown. The last bin includes the overflow events.
png pdf	Figure 2-b: Distribution of ${{p_{\mathrm {T}}} ^\text {miss}}$ for simulated SM backgrounds (stacked histograms), with the hadronic baseline selection and after the additional Z candidate selection. Expected signal contributions for two example mass points (dotted lines) are also shown. The last bin includes the overflow events.
png pdf	Figure 3: Definition of the search and control regions in the plane of subleading vs. leading jet mass. The search region (red central box), with both ${m_{\text {jet}}}$ values lying within the Z signal window, defines the acceptance for potential signal; the leading-jet mass sideband (dark blue), with subleading jet within and leading jet outside the signal window, is used to measure the background normalization; the ${{p_{\mathrm {T}}} ^\text {miss}}$ CR (light blue), with both leading- and subleading-jet ${m_{\text {jet}}}$ values lying outside the signal window, is used to derive the ${{p_{\mathrm {T}}} ^\text {miss}}$ shape in the search region.
png pdf	Figure 4: Leading AK8 jet ${m_{\text {jet}}}$ shape fit in the mass sidebands. The Z candidate selection is applied and the subleading AK8 jet ${m_{\text {jet}}}$ value is required to lie in the Z signal window. The blue hatched region represents the $ \pm $1 standard deviation uncertainty in the fit to the mass sideband performed with a linear function, which is indicated by the blue line. The stacked histogram shows the background from simulation scaled to the data. Expected signal contributions for two example mass points are also shown.
png pdf	Figure 5: Comparison of the ${{p_{\mathrm {T}}} ^\text {miss}}$ shape in the search and control regions in simulation. The upper panels show the unit-normalized ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions $f^{\text {MC}}({{p_{\mathrm {T}}} ^\text {miss}})$ in the two regions, while the lower panels show the ratio of the number of events in the search region to that in the control region. This comparison is done for two main background components: ${\mathrm{Z} \to \nu \bar{\nu}}$ (left) and ${\mathrm{t} {}\mathrm{\bar{t}}}$ plus W+jets (right). In the lower panel the statistical uncertainties in the search and control region yields are denoted by the shading and vertical bars, respectively, and a fit to a constant is included to show the average ratio.
png pdf	Figure 5-a: Comparison of the ${{p_{\mathrm {T}}} ^\text {miss}}$ shape in the search and control regions in simulation. The upper panel shows the unit-normalized ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions $f^{\text {MC}}({{p_{\mathrm {T}}} ^\text {miss}})$ in the two regions, while the lower panel shows the ratio of the number of events in the search region to that in the control region. This comparison is done for the ${\mathrm{Z} \to \nu \bar{\nu}}$ background component. In the lower panel the statistical uncertainties in the search and control region yields are denoted by the shading and vertical bars, respectively, and a fit to a constant is included to show the average ratio.
png pdf	Figure 5-b: Comparison of the ${{p_{\mathrm {T}}} ^\text {miss}}$ shape in the search and control regions in simulation. The upper panel shows the unit-normalized ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions $f^{\text {MC}}({{p_{\mathrm {T}}} ^\text {miss}})$ in the two regions, while the lower panel shows the ratio of the number of events in the search region to that in the control region. This comparison is done for the ${\mathrm{t} {}\mathrm{\bar{t}}}$ plus W+jets background components. In the lower panel the statistical uncertainties in the search and control region yields are denoted by the shading and vertical bars, respectively, and a fit to a constant is included to show the average ratio.
png pdf	Figure 6: Results of the closure test in which the background estimation method based on control samples in data is applied to simulation and compared with the direct yield, in the analysis search bins. Expected signal contribution for one example mass point is also shown. The lower panel shows the ratio of the prediction to the direct yield. The gray band shows the statistical uncertainty in the direct yield, and the error bars on the points represent the total uncertainty in the prediction.
png pdf	Figure 7: Comparison of the ${{p_{\mathrm {T}}} ^\text {miss}}$ shape between the Z signal window and ${{p_{\mathrm {T}}} ^\text {miss}}$ control region for the photon (left) and single-lepton (right) validation samples in data. The upper panels show the unit-normalized ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions $f^{\text {data}}({{p_{\mathrm {T}}} ^\text {miss}})$ in the two regions, while the lower panels show the ratio of the number of events in the search region to that in the control region. A fit to a constant is included in the lower panels to show the average ratio. The horizontal bars on the markers indicate the widths of the search bins. In the lower panel the statistical uncertainties in the search and control region yields are denoted by the shading and vertical bars, respectively.
png pdf	Figure 7-a: Comparison of the ${{p_{\mathrm {T}}} ^\text {miss}}$ shape between the Z signal window and ${{p_{\mathrm {T}}} ^\text {miss}}$ control region for the photon validation sample in data. The upper panel shows the unit-normalized ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions $f^{\text {data}}({{p_{\mathrm {T}}} ^\text {miss}})$ in the two regions, while the lower panel shows the ratio of the number of events in the search region to that in the control region. A fit to a constant is included in the lower panel to show the average ratio. The horizontal bars on the markers indicate the widths of the search bins. In the lower panel the statistical uncertainties in the search and control region yields are denoted by the shading and vertical bars, respectively.
png pdf	Figure 7-b: Comparison of the ${{p_{\mathrm {T}}} ^\text {miss}}$ shape between the Z signal window and ${{p_{\mathrm {T}}} ^\text {miss}}$ control region for the single-lepton validation sample in data. The upper panel shows the unit-normalized ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions $f^{\text {data}}({{p_{\mathrm {T}}} ^\text {miss}})$ in the two regions, while the lower panel shows the ratio of the number of events in the search region to that in the control region. A fit to a constant is included in the lower panel to show the average ratio. The horizontal bars on the markers indicate the widths of the search bins. In the lower panel the statistical uncertainties in the search and control region yields are denoted by the shading and vertical bars, respectively.
png pdf root	Figure 8: Observed data and background prediction as functions of ${{p_{\mathrm {T}}} ^\text {miss}}$. The horizontal bar associated with each data point represents the width of the corresponding bin. The red hatched region denotes the expected statistical and systematic uncertainties added in quadrature. Expected signal contribution for one example mass point is also shown.
png pdf root	Figure 9: The 95% CL upper limit on the production cross section for the T5ZZ signal model as a function of the gluino mass. The solid black curve shows the observed exclusion limit. The dashed black curve presents the expected limit while the green and yellow bands represent the $ \pm $1 and $ \pm $2 standard deviation uncertainty ranges. The approximate-NNLO+NNLL cross sections [41,42,43,44,45] are shown in the solid blue curve while the dashed blue curves show their theoretical uncertainties [84]. The T5ZZ model assumes a 100% branching fraction for the $\tilde{\chi}^{0}_{2}$ to decay to the Z boson and $\tilde{\chi}^{0}_{1}$.

Tables
png pdf	Table 1: Summary of systematic uncertainties, where the ranges refer to different ${{p_{\mathrm {T}}} ^\text {miss}}$ bins. In the last column we distinguish uncertainties that affect the normalizations ("norm."), the shapes of distributions, or both.
png pdf	Table 2: Number of events in the ${{p_{\mathrm {T}}} ^\text {miss}}$ CR, transfer factor, background prediction, and observed yield in each of the six ${{p_{\mathrm {T}}} ^\text {miss}}$ bins. Where two uncertainties are quoted, the first is statistical and the second systematic. The systematic uncertainties in the background prediction include the shape uncertainties in addition to the uncertainty in $\mathcal {T}$. Also listed in the last column is the number of expected signal events and corresponding statistical uncertainties for one example mass point.

Summary

Results are presented of a search for events with two hadronically decaying, highly energetic Z bosons and large transverse momentum imbalance, in proton-proton collisions at $\sqrt{s} = $ 13 TeV. The sample corresponds to an integrated luminosity of 137 fb$^{-1}$. The signature for a Z boson candidate is a wide-cone jet having a measured mass compatible with the Z boson mass. Yields from standard model background processes, which are small for events with the largest transverse momentum imbalance, are estimated from the data in jet mass sidebands. No evidence for physics beyond the standard model is observed. The reach of the search is interpreted in a simplified supersymmetric model of gluino pair production in which each gluino decays to a low-momentum quark pair and the next-to-lightest supersymmetric particle (NLSP), and the latter decays to a Z boson and the lightest supersymmetric particle (LSP). With the further assumption of a large mass splitting between the NLSP and LSP, the data exclude gluino masses below 1920 GeV at 95% confidence level. This is the first search for beyond-standard-model production of pairs of boosted Z bosons plus large missing transverse momentum.

Additional Figures
png pdf root	Additional Figure 1: Pre-fit background covariance matrix (left) and correlation matrix (right), for the six ${{p_{\mathrm {T}}} ^\text {miss}}$ bins.
png pdf root	Additional Figure 1-a: Pre-fit background covariance matrix, for the six ${{p_{\mathrm {T}}} ^\text {miss}}$ bins.
png pdf root	Additional Figure 1-b: Pre-fit background correlation matrix, for the six ${{p_{\mathrm {T}}} ^\text {miss}}$ bins.
png pdf	Additional Figure 2: The efficiency to reconstruct $ {\mathrm {Z}} \to {{\mathrm {q}} {\overline {\mathrm {q}}}} $ decays as an AK8 jet as a function of the generator Z ${p_{\mathrm {T}}}$ is shown by the open circles. The efficiency for the jets to pass the Z-mass window cut is shown by the full circles. The plot is made for an example mass point $ {m({{\mathrm {\tilde{g}}}})} = $ 1300 GeV.
png pdf	Additional Figure 3: The efficiency to reconstruct $ {\mathrm {Z}} \to {{\mathrm {q}} {\overline {\mathrm {q}}}} $ decays as an AK8 jet as a function of the generator Z ${p_{\mathrm {T}}}$ is shown by the open circles. The efficiency for the jets to pass the Z-mass window cut is shown by the full circles. The plot is made for an example mass point $ {m({{\mathrm {\tilde{g}}}})} = $ 2100 GeV.

Additional Tables
png pdf	Additional Table 1: Observed numbers of events and post-fit backgrounds in each of the six ${{p_{\mathrm {T}}} ^\text {miss}}$ bins.
png pdf	Additional Table 2: Observed significance (in standard deviations) of the T5ZZ signal model as a function of the gluino mass.
png pdf	Additional Table 3: Observed upper limits in cross-section of the T5ZZ signal model as a function of the gluino mass.
png pdf	Additional Table 4: Cut flow for the signal for two example mass points of the T5ZZ signal model for an integrated luminosity of 137 fb$^{-1}$. Here the hadronic baseline is defined by $ {N_{\text {jet}}} \ge $ 2, $ {{p_{\mathrm {T}}} ^\text {miss}} > $ 300 GeV, $ {H_{\mathrm {T}}} > $ 300 GeV, $ {\Delta \phi _{j,\, {\vec{H}_{\text {T}}^{\text {miss}}}}} $ cuts, and the isolated photon, lepton and track veto.

References
1	ATLAS Collaboration	Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC	PLB 716 (2012) 1	1207.7214
2	CMS Collaboration	Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC	PLB 716 (2012) 30	CMS-HIG-12-028 1207.7235
3	CMS Collaboration	Observation of a new boson with mass near 125 GeV in pp collisions at $ \sqrt{s} = $ 7 and 8 TeV	JHEP 06 (2013) 081	CMS-HIG-12-036 1303.4571
4	R. Barbieri and G. F. Giudice	Upper bounds on supersymmetric particle masses	NPB 306 (1988) 63
5	S. Dimopoulos and G. F. Giudice	Naturalness constraints in supersymmetric theories with nonuniversal soft terms	PLB 357 (1995) 573	hep-ph/9507282
6	R. Barbieri and D. Pappadopulo	S-particles at their naturalness limits	JHEP 10 (2009) 061	0906.4546
7	M. Papucci, J. T. Ruderman, and A. Weiler	Natural SUSY endures	JHEP 09 (2012) 035	1110.6926
8	P. Fayet and S. Ferrara	Supersymmetry	PR 32 (1977) 249
9	H. P. Nilles	Supersymmetry, supergravity and particle physics	PR 110 (1984) 1
10	S. P. Martin	A supersymmetry primer	Adv. Ser. Direct. High Energy Phys. 21 (2010) 1	hep-ph/9709356
11	P. Fayet	Supergauge invariant extension of the Higgs mechanism and a model for the electron and its neutrino	NPB 90 (1975) 104
12	G. R. Farrar and P. Fayet	Phenomenology of the production, decay, and detection of new hadronic states associated with supersymmetry	PLB 76 (1978) 575
13	CMS Collaboration	Search for supersymmetry in proton-proton collisions at 13 TeV in final states with jets and missing transverse momentum	JHEP 10 (2019) 244	CMS-SUS-19-006 1908.04722
14	CMS Collaboration	Searches for physics beyond the standard model with the $ M_\mathrm{T2} $ variable in hadronic final states with and without disappearing tracks in proton-proton collisions at $ \sqrt{s}= $ 13 TeV	EPJC 80 (2020) 3	CMS-SUS-19-005 1909.03460
15	CMS Collaboration	Search for supersymmetry in pp collisions at $ \sqrt{s}= $ 13 TeV with 137 fb$ ^{-1} $ in final states with a single lepton using the sum of masses of large-radius jets	PRD 101 (2020) 052010	CMS-SUS-19-007 1911.07558
16	CMS Collaboration	Search for physics beyond the standard model in events with jets and two same-sign or at least three charged leptons in proton-proton collisions at $ \sqrt{s}= $ 13 TeV	Accepted by EPJC	CMS-SUS-19-008 2001.10086
17	H. Baer et al.	Natural SUSY with a bino- or wino-like LSP	PRD 91 (2015) 075005	1501.06357
18	N. Arkani-Hamed et al.	MARMOSET: The path from LHC data to the new standard model via on-shell effective theories		hep-ph/0703088
19	J. Alwall, M.-P. Le, M. Lisanti, and J. G. Wacker	Model-independent jets plus missing energy searches	PRD 79 (2009) 015005	0809.3264
20	J. Alwall, P. Schuster, and N. Toro	Simplified models for a first characterization of new physics at the LHC	PRD 79 (2009) 075020	0810.3921
21	D. Alves et al.	Simplified models for LHC new physics searches	JPG 39 (2012) 105005	1105.2838
22	CMS Collaboration	The CMS experiment at the CERN LHC	JINST 3 (2008) S08004	CMS-00-001
23	CMS Collaboration	The CMS trigger system	JINST 12 (2017) P01020	CMS-TRG-12-001 1609.02366
24	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
25	J. Alwall et al.	Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions	EPJC 53 (2008) 473	0706.2569
26	R. Frederix and S. Frixione	Merging meets matching in MC@NLO	JHEP 12 (2012) 061	1209.6215
27	P. Nason	A new method for combining NLO QCD with shower Monte Carlo algorithms	JHEP 11 (2004) 040	hep-ph/0409146
28	S. Frixione, P. Nason, and C. Oleari	Matching NLO QCD computations with parton shower simulations: the POWHEG method	JHEP 11 (2007) 070	0709.2092
29	S. Alioli, P. Nason, C. Oleari, and E. Re	A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX	JHEP 06 (2010) 043	1002.2581
30	S. Alioli, P. Nason, C. Oleari, and E. Re	NLO single-top production matched with shower in POWHEG: $ s $- and $ t $-channel contributions	JHEP 09 (2009) 111	0907.4076
31	E. Re	Single-top Wt-channel production matched with parton showers using the POWHEG method	EPJC 71 (2011) 1547	1009.2450
32	T. Melia, P. Nason, R. Rontsch, and G. Zanderighi	W$ ^+ $W$ ^- $, WZ and ZZ production in the POWHEG BOX	JHEP 11 (2011) 078	1107.5051
33	M. Beneke, P. Falgari, S. Klein, and C. Schwinn	Hadronic top-quark pair production with NNLL threshold resummation	NPB 855 (2012) 695	1109.1536
34	M. Cacciari et al.	Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation	PLB 710 (2012) 612	1111.5869
35	P. Barnreuther, M. Czakon, and A. Mitov	Percent-level-precision physics at the Tevatron: next-to-next-to-leading order QCD corrections to $ \mathrm{q\bar{q}}\to\mathrm{t\bar{t}} +X $	PRL 109 (2012) 132001	1204.5201
36	M. Czakon and A. Mitov	NNLO corrections to top-pair production at hadron colliders: the all-fermionic scattering channels	JHEP 12 (2012) 054	1207.0236
37	M. Czakon and A. Mitov	NNLO corrections to top pair production at hadron colliders: the quark-gluon reaction	JHEP 01 (2013) 080	1210.6832
38	M. Czakon, P. Fiedler, and A. Mitov	Total top-quark pair-production cross section at hadron colliders through $ O({\alpha_S}^4) $	PRL 110 (2013) 252004	1303.6254
39	R. Gavin, Y. Li, F. Petriello, and S. Quackenbush	W physics at the LHC with FEWZ 2.1	CPC 184 (2013) 208	1201.5896
40	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	1011.3540
41	W. Beenakker, R. Hopker, M. Spira, and P. M. Zerwas	Squark and gluino production at hadron colliders	NPB 492 (1997) 51	hep-ph/9610490
42	A. Kulesza and L. Motyka	Threshold resummation for squark-antisquark and gluino-pair production at the LHC	PRL 102 (2009) 111802	0807.2405
43	A. Kulesza and L. Motyka	Soft gluon resummation for the production of gluino-gluino and squark-antisquark pairs at the LHC	PRD 80 (2009) 095004	0905.4749
44	W. Beenakker et al.	Soft-gluon resummation for squark and gluino hadroproduction	JHEP 12 (2009) 041	0909.4418
45	W. Beenakker et al.	Squark and gluino hadroproduction	Int. J. Mod. Phys. A 26 (2011) 2637	1105.1110
46	W. Beenakker et al.	NNLL-fast: predictions for coloured supersymmetric particle production at the LHC with threshold and Coulomb resummation	JHEP 12 (2016) 133	1607.07741
47	W. Beenakker et al.	NNLL resummation for squark-antisquark pair production at the LHC	JHEP 01 (2012) 076	1110.2446
48	W. Beenakker et al.	Towards NNLL resummation: hard matching coefficients for squark and gluino hadroproduction	JHEP 10 (2013) 120	1304.6354
49	W. Beenakker et al.	NNLL resummation for squark and gluino production at the LHC	JHEP 12 (2014) 023	1404.3134
50	W. Beenakker et al.	Stop production at hadron colliders	NPB 515 (1998) 3	hep-ph/9710451
51	W. Beenakker et al.	Supersymmetric top and bottom squark production at hadron colliders	JHEP 08 (2010) 098	1006.4771
52	W. Beenakker et al.	NNLL resummation for stop pair-production at the LHC	JHEP 05 (2016) 153	1601.02954
53	T. Sjostrand et al.	An introduction to PYTHIA 8.2	CPC 191 (2015) 159	1410.3012
54	CMS Collaboration	Event generator tunes obtained from underlying event and multiparton scattering measurements	EPJC 76 (2016) 155	CMS-GEN-14-001 1512.00815
55	CMS Collaboration	Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements	EPJC 80 (2020) 4	CMS-GEN-17-001 1903.12179
56	NNPDF Collaboration	Parton distributions for the LHC Run II	JHEP 04 (2015) 040	1410.8849
57	NNPDF Collaboration	Parton distributions from high-precision collider data	EPJC 77 (2017) 663	1706.00428
58	GEANT4 Collaboration	GEANT4---a simulation toolkit	NIMA 506 (2003) 250
59	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
60	CMS Collaboration	Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s} = $ 13 TeV using the CMS detector	JINST 14 (2019) P07004	CMS-JME-17-001 1903.06078
61	M. Cacciari, G. P. Salam, and G. Soyez	The anti-$ {k_{\mathrm{T}}} $ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
62	M. Cacciari, G. P. Salam, and G. Soyez	FastJet user manual	EPJC 72 (2012) 1896	1111.6097
63	CMS Collaboration	Jet performance in pp collisions at $ \sqrt{s}= $ 7 TeV	CDS
64	CMS Collaboration	Jet algorithms performance in 13 TeV data	CMS-PAS-JME-16-003	CMS-PAS-JME-16-003
65	CMS Collaboration	Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV	JINST 12 (2017) P02014	CMS-JME-13-004 1607.03663
66	M. Cacciari and G. P. Salam	Pileup subtraction using jet areas	PLB 659 (2008) 119	0707.1378
67	A. J. Larkoski, S. Marzani, G. Soyez, and J. Thaler	Soft Drop	JHEP 05 (2014) 146	1402.2657
68	D. Bertolini, P. Harris, M. Low, and N. Tran	Pileup Per Particle Identification	JHEP 10 (2014) 059	1407.6013
69	CMS Collaboration	Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV	JINST 13 (2018) P05011	CMS-BTV-16-002 1712.07158
70	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
71	CMS Collaboration	Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s} = $ 13 TeV	JINST 13 (2018) P06015	CMS-MUO-16-001 1804.04528
72	K. Rehermann and B. Tweedie	Efficient identification of boosted semileptonic top quarks at the LHC	JHEP 03 (2011) 059	1007.2221
73	CMS Collaboration	Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV	JINST 10 (2015) P08010	CMS-EGM-14-001 1502.02702
74	UA1 Collaboration	Experimental observation of isolated large transverse energy electrons with associated missing energy at $ \sqrt{s}= $ 540 GeV	PLB 122 (1983) 103
75	CMS Collaboration	CMS luminosity measurements for the 2016 data-taking period	CMS-PAS-LUM-17-001	CMS-PAS-LUM-17-001
76	CMS Collaboration	CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s} = $ 13 TeV	CMS-PAS-LUM-17-004	CMS-PAS-LUM-17-004
77	CMS Collaboration	CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s}= $ 13 TeV	CMS-PAS-LUM-18-002	CMS-PAS-LUM-18-002
78	S. Catani, D. de Florian, M. Grazzini, and P. Nason	Soft gluon resummation for Higgs boson production at hadron colliders	JHEP 07 (2003) 028	hep-ph/0306211
79	M. Cacciari et al.	The $ \mathrm{t\bar{t}} $ cross-section at 1.8 TeV and 1.96 TeV: a study of the systematics due to parton densities and scale dependence	JHEP 04 (2004) 068	hep-ph/0303085
80	G. Cowan, K. Cranmer, E. Gross, and O. Vitells	Asymptotic formulae for likelihood-based tests of new physics	EPJC 71 (2011) 1554	1007.1727
81	A. L. Read	Presentation of search results: the CLs technique	JPG 28 (2002) 2693
82	T. Junk	Confidence level computation for combining searches with small statistics	NIMA 434 (1999) 435	hep-ex/9902006
83	ATLAS and CMS Collaborations	Procedure for the LHC Higgs boson search combination in Summer 2011	CMS-NOTE-2011-005
84	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) 3174	1407.5066

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