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CMS-HIG-19-012 ; CERN-EP-2020-120

Search for decays of the 125 GeV Higgs boson into a Z boson and a $\rho$ or $\phi$ meson

CMS Collaboration

9 July 2020

JHEP 11 (2020) 039

Abstract: Decays of the 125 GeV Higgs boson into a Z boson and a $\rho^{0}(770)$ or $\phi(1020)$ meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at $\sqrt{s} = $ 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb$^{-1}$. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the $\rho$ and $\phi$ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and $\rho$ or $\phi$ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Z$\rho$ and Z$\phi$ are determined to be 1.04-1.31% and 0.31-0.40%, respectively, where the ranges reflect the considered polarization scenarios; these values are 740-940 and 730-950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels.

Links: e-print arXiv:2007.05122 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ;

Figures
png pdf	Figure 1: Feynman diagrams that contribute to the decay of a Higgs boson into a heavy vector boson and a vector meson. The grey oval shape represents the meson. The two indirect processes (left and middle), where the meson originates from an off-shell Z boson or $\gamma ^{*}$, contribute the most to the total branching fraction in the SM.
png pdf	Figure 1-a: Feynman diagram that contributes to the decay of a Higgs boson into a heavy vector boson and a vector meson. The grey oval shape represents the meson. This indirect process, where the meson originates from an off-shell Z boson, is one of two that contribute the most to the total branching fraction in the SM.
png pdf	Figure 1-b: Feynman diagram that contributes to the decay of a Higgs boson into a heavy vector boson and a vector meson. The grey oval shape represents the meson. This indirect process, where the meson originates from a $\gamma ^{*}$, is one of two that contribute the most to the total branching fraction in the SM.
png pdf	Figure 1-c: Feynman diagram that contributes to the decay of a Higgs boson into a heavy vector boson and a vector meson. The grey oval shape represents the meson.
png pdf	Figure 2: The angular distance $\Delta R$ between the two tracks from the meson decay in $\mathrm{H} \to \mathrm{Z} \rho $ events (dashed red) and in $\mathrm{H} \to \mathrm{Z} \phi $ events (dotted blue). The separation is calculated between reconstructed tracks that are matched to the generator-level pions (kaons) to ensure that the tracks originate from the $\rho$ ($\phi$) decay. Both contributions are normalized to the same area.
png pdf	Figure 3: The transverse momentum distribution for the track that has the larger ${p_{\mathrm {T}}}$ out of the two tracks selected as the $\rho$ or $\phi$ candidate. The distribution is shown for events that pass the meson candidate selection described in the text, but not the requirement that one of the tracks must have $ {p_{\mathrm {T}}} > $ 10 GeV. This distribution is shown for the $\mathrm{H} \to \mathrm{Z} \rho $ decay (dashed red), the $\mathrm{H} \to \mathrm{Z} \phi $ decay (dotted blue) and the background from Drell-Yan events (solid black). All contributions are normalized to the same area.
png pdf	Figure 4: The ditrack isolation sum in the $\ell \ell \pi \pi $ (left) and $\ell \ell \mathrm{K} \mathrm{K} $ (right) channels, combining the $\mu \mu $ and ee channels for all the data-taking years. The distribution in data, as well as in the simulated $\mathrm{H} \to \mathrm{Z} \rho $ and $\mathrm{H} \to \mathrm{Z} \phi $ signals is shown. A branching fraction of 10 (5)% for the $\mathrm{H} \to \mathrm{Z} \rho $ ($\mathrm{H} \to \mathrm{Z} \phi $) signal is assumed. The isolation sum is shown after applying all selection criteria apart from the ditrack isolation requirement. The ditrack invariant mass requirement is also applied. Only events in which the dilepton plus ditrack invariant mass is in the range 120-130 GeV are considered. The dashed line indicates the boundary of the region used in the analysis, for which the isolation sum is required to be smaller than 0.5 GeV.
png pdf	Figure 4-a: The ditrack isolation sum in the $\ell \ell \pi \pi $ channel, combining the $\mu \mu $ and ee channels for all the data-taking years. The distribution in data, as well as in the simulated $\mathrm{H} \to \mathrm{Z} \rho $ signal is shown. A branching fraction of 10% for the $\mathrm{H} \to \mathrm{Z} \rho $ signal is assumed. The isolation sum is shown after applying all selection criteria apart from the ditrack isolation requirement. The ditrack invariant mass requirement is also applied. Only events in which the dilepton plus ditrack invariant mass is in the range 120-130 GeV are considered. The dashed line indicates the boundary of the region used in the analysis, for which the isolation sum is required to be smaller than 0.5 GeV.
png pdf	Figure 4-b: The ditrack isolation sum in the $\ell \ell \mathrm{K} \mathrm{K} $ channel, combining the $\mu \mu $ and ee channels for all the data-taking years. The distribution in data, as well as in the simulated $\mathrm{H} \to \mathrm{Z} \phi $ signal is shown. A branching fraction of 5% for the $\mathrm{H} \to \mathrm{Z} \phi $ signal is assumed. The isolation sum is shown after applying all selection criteria apart from the ditrack isolation requirement. The ditrack invariant mass requirement is also applied. Only events in which the dilepton plus ditrack invariant mass is in the range 120-130 GeV are considered. The dashed line indicates the boundary of the region used in the analysis, for which the isolation sum is required to be smaller than 0.5 GeV.
png pdf	Figure 5: Distribution of the ditrack invariant mass in simulated $\mathrm{H} \to \mathrm{Z} \rho $ events passing the $\ell \ell \pi \pi $ selection criteria (left) and in simulated $\mathrm{H} \to \mathrm{Z} \phi $ events passing the $\ell \ell \mathrm{K} \mathrm{K} $ selection criteria (right). These masses are calculated assuming the charged particle mass equals the pion mass in the $\ell \ell \pi \pi $ selection and assuming the charged particle mass equals the kaon mass in the $\ell \ell \mathrm{K} \mathrm{K} $ selection. The events pass all selection criteria described in the text, apart from the requirements on the ditrack invariant mass window. The dashed lines indicate the region selected in the analysis.
png pdf	Figure 5-a: Distribution of the ditrack invariant mass in simulated $\mathrm{H} \to \mathrm{Z} \rho $ events passing the $\ell \ell \pi \pi $ selection criteria.These masses are calculated assuming the charged particle mass equals the pion mass. The events pass all selection criteria described in the text, apart from the requirements on the ditrack invariant mass window. The dashed lines indicate the region selected in the analysis.
png pdf	Figure 5-b: Distribution of the ditrack invariant mass in simulated $\mathrm{H} \to \mathrm{Z} \rho $ events passing the $\ell \ell \pi \pi $ selection criteria. These masses are calculated assuming the charged particle mass equals the kaon mass. The events pass all selection criteria described in the text, apart from the requirements on the ditrack invariant mass window. The dashed lines indicate the region selected in the analysis.
png pdf	Figure 6: Distributions of $m_{\ell \ell \pi \pi}$ (left) and $m_{\ell \ell \mathrm{K} \mathrm{K}}$ (right). For visualization the $\mu \mu $ and ee channels, as well as all three data-taking periods, are combined. Also shown are the $\mathrm{H} \to \mathrm{Z} \rho $ and $\mathrm{H} \to \mathrm{Z} \phi $ signals, in the isotropic-decay scenario and assuming branching fractions of 3.0 and 0.7%, respectively. The ratio between the data and the background model is shown in the lower panels.
png pdf	Figure 6-a: Distribution of $m_{\ell \ell \pi \pi}$. For visualization the $\mu \mu $ and ee channels, as well as all three data-taking periods, are combined. Also shown is the $\mathrm{H} \to \mathrm{Z} \rho $ signal, in the isotropic-decay scenario and assuming branching fractions of 3.0% The ratio between the data and the background model is shown in the lower panel.
png pdf	Figure 6-b: Distribution of $m_{\ell \ell \mathrm{K} \mathrm{K}}$. For visualization the $\mu \mu $ and ee channels, as well as all three data-taking periods, are combined. Also shown is the $\mathrm{H} \to \mathrm{Z} \phi $ signal, in the isotropic-decay scenario and assuming branching fractions of 0.7% The ratio between the data and the background model is shown in the lower panel.

Tables
png pdf	Table 1: The effect on the signal yields of reweighting to the extreme polarization scenarios, described in more detail in the text, relative to the scenario with isotropic decays. The change in the fraction of signal events that pass the selection criteria affects the final results of the analysis.
png pdf	Table 2: Effect of systematic uncertainties on the simulated signal. The ranges reflect differences between channels and data-taking periods.
png pdf	Table 3: Observed and expected 95% CL upper limits on $\mathcal {B}(\mathrm{H} \to \mathrm{Z} \rho)$, for different polarizations.
png pdf	Table 4: Observed and expected 95% CL upper limits on $\mathcal {B}(\mathrm{H} \to \mathrm{Z} \phi)$, for different polarizations.

Summary

A search has been presented for the rare decay of the Higgs boson (H) into a Z boson and a $\rho$ or a $\phi$ meson in the dilepton-$\pi^{+}\pi^{-}$ final states of the $\mathrm{H}zrho$ decay, and in the dilepton-$\mathrm{K^{+}}\mathrm{K^{-}}$ final states of the $\mathrm{H} \to \mathrm{Z}\phi$ decay. The search used a sample of proton-proton collisions, collected by the CMS experiment at a centre-of-mass energy of 13 TeV from 2016 to 2018 and corresponding to an integrated luminosity of 137 fb$^{-1}$. Upper limits on the branching fractions $\mathcal{B}(\mathrm{H} \to \mathrm{Z}\rho)$ and $\mathcal{B}(\mathrm{H} \to \mathrm{Z}\phi)$ have been set at the 95% confidence level for various polarization scenarios. The upper limits on $\mathcal{B}(\mathrm{H} \to \mathrm{Z}\rho)$ are in the range 1.04-1.31%, or 740-940 times the standard model expectation, while the upper limits on $\mathcal{B}(\mathrm{H} \to \mathrm{Z}\phi)$ range from 0.31 to 0.40%, or 730-950 times the standard model expectation. These results constitute the first experimental limits on the two decay channels.

Additional Figures
png pdf	Additional Figure 1: Distribution of $m_{\ell \ell {\pi} {\pi}}$, combining the dielectron and dimuon channels for all three data taking years. The $ {\mathrm {H}} \to {\mathrm {Z}} {\rho} $ signal, in the isotropic-decay scenario assuming a branching fraction of 3%, is also shown. This figure only shows the mass range containing most of the signal, which is a subset of the mass range used in the fit.
png pdf	Additional Figure 2: Distribution of $m_{\ell \ell {\mathrm {K}} {\mathrm {K}}}$, combining the dielectron and dimuon channels for all three data taking years. The $ {\mathrm {H}} \to {\mathrm {Z}} $ signal, in the isotropic-decay scenario assuming a branching fraction of 0.7%, is also shown. This figure only shows the mass range containing most of the signal, which is a subset of the mass range used in the fit.
png pdf	Additional Figure 3: Observed and expected 95% CL upper limits on the branching ratio $\mathcal {B}({\mathrm {H}} \to {\mathrm {Z}} {\rho})$, for the different polarization scenarios considered. The Z boson and the $ {\rho} $ meson are either both transversely polarized (transverse) or both longitudinally polarized (longitudinal). The limits for each polarization scenario are obtained using the same data; differences in the limits arise only from changes in the expected signal yield.
png pdf	Additional Figure 4: Observed and expected 95% CL upper limits on the branching ratio $\mathcal {B}({\mathrm {H}} \to {\mathrm {Z}})$, for the different polarization scenarios considered. The Z boson and the $\phi$ meson are either both transversely polarized (transverse) or both longitudinally polarized (longitudinal). The limits for each polarization scenario are obtained using the same data; differences in the limits arise only from changes in the expected signal yield.
png pdf	Additional Figure 5: View of a candidate event with two muons (red lines) compatible with having originated from a Z boson, and two charged kaon tracks compatible with having originated from a $\phi$ meson. In this view all charged particle tracks in the event are shown.
png pdf	Additional Figure 6: View of a candidate event with two muons (red lines) compatible with having originated from a Z boson, and two charged kaon tracks (yellow lines) compatible with having originated from a $\phi$ meson. In this view only the two charged kaon tracks are shown.

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	F. Englert and R. Brout	Broken symmetry and the mass of gauge vector mesons	PRL 13 (1964) 321
5	P. W. Higgs	Broken symmetries, massless particles and gauge fields	PL12 (1964) 132
6	P. W. Higgs	Broken symmetries and the masses of gauge bosons	PRL 13 (1964) 508
7	G. S. Guralnik, C. R. Hagen, and T. W. B. Kibble	Global conservation laws and massless particles	PRL 13 (1964) 585
8	P. W. Higgs	Spontaneous symmetry breakdown without massless bosons	PR145 (1966) 1156
9	T. W. B. Kibble	Symmetry breaking in non-abelian gauge theories	PR155 (1967) 1554
10	ATLAS Collaboration	Measurement of Higgs boson production in the diphoton decay channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector	PRD 90 (2014) 112015	1408.7084
11	CMS Collaboration	Observation of the diphoton decay of the Higgs boson and measurement of its properties	EPJC 74 (2014) 3076	CMS-HIG-13-001 1407.0558
12	ATLAS Collaboration	Measurements of Higgs boson production and couplings in the four-lepton channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector	PRD 91 (2015) 012006	1408.5191
13	CMS Collaboration	Measurement of the properties of a Higgs boson in the four-lepton final state	PRD 89 (2014) 092007	CMS-HIG-13-002 1312.5353
14	ATLAS Collaboration	Observation and measurement of Higgs boson decays to WW$ ^* $ with the ATLAS detector	PRD 92 (2015) 012006	1412.2641
15	ATLAS Collaboration	Study of (W/Z)H production and Higgs boson couplings using $ H \rightarrow WW^{\ast} $ decays with the ATLAS detector	JHEP 08 (2015) 137	1506.06641
16	CMS Collaboration	Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states	JHEP 01 (2014) 096	CMS-HIG-13-023 1312.1129
17	ATLAS and CMS Collaborations	Measurements of the Higgs boson production and decay rates and constraints on its couplings from a combined ATLAS and CMS analysis of the LHC pp collision data at $ \sqrt{s}= $ 7 and 8 TeV	JHEP 08 (2016) 045	1606.02266
18	ATLAS Collaboration	Cross-section measurements of the Higgs boson decaying into a pair of $ \tau $-leptons in proton-proton collisions at $ \sqrt{s}= $ 13 TeV with the ATLAS detector	PRD 99 (2019) 072001	1811.08856
19	CMS Collaboration	Observation of the Higgs boson decay to a pair of $ \tau $ leptons with the CMS detector	PLB 779 (2018) 283	CMS-HIG-16-043 1708.00373
20	ATLAS Collaboration	Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector	PLB 784 (2018) 173	1806.00425
21	CMS Collaboration	Observation of $ \mathrm{t\overline{t}} $H production	PRL 120 (2018) 231801	CMS-HIG-17-035 1804.02610
22	ATLAS Collaboration	Observation of $ H \rightarrow b\bar{b} $ decays and $ VH $ production with the ATLAS detector	PLB 786 (2018) 59	1808.08238
23	CMS Collaboration	Observation of Higgs boson decay to bottom quarks	PRL 121 (2018) 121801	CMS-HIG-18-016 1808.08242
24	ATLAS Collaboration	Search for the dimuon decay of the Higgs boson in $ pp $ collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector	PRL 119 (2017) 051802	1705.04582
25	CMS Collaboration	Search for the Higgs boson decaying to two muons in proton-proton collisions at $ \sqrt{s} = $ 13 TeV	PRL 122 (2019) 021801	CMS-HIG-17-019 1807.06325
26	ATLAS Collaboration	Search for the decay of the Higgs boson to charm quarks with the ATLAS experiment	PRL 120 (2018) 211802	1802.04329
27	CMS Collaboration	A search for the standard model Higgs boson decaying to charm quarks	JHEP 03 (2020) 131	CMS-HIG-18-031 1912.01662
28	G. T. Bodwin, F. Petriello, S. Stoynev, and M. Velasco	Higgs boson decays to quarkonia and the $ H\bar{c}c $ coupling	PRD 88 (2013) 053003	1306.5770
29	A. L. Kagan et al.	Exclusive window onto Higgs Yukawa couplings	PRL 114 (2015) 101802	1406.1722
30	S. Alte, M. Konig, and M. Neubert	Exclusive weak radiative Higgs decays in the standard model and beyond	JHEP 12 (2016) 037	1609.06310
31	CMS Collaboration	Search for rare decays of Z and Higgs bosons to J$ /\psi $ and a photon in proton-proton collisions at $ \sqrt{s} = $ 13 TeV	EPJC 79 (2019) 94	CMS-SMP-17-012 1810.10056
32	ATLAS Collaboration	Searches for exclusive Higgs and $ Z $ boson decays into $ J/\psi\gamma $, $ \psi(\text{2S})\gamma $, and $ \Upsilon(\text{nS})\gamma $ at $ \sqrt{s}= $ 13 TeV with the ATLAS detector	PLB 786 (2018) 134	1807.00802
33	ATLAS Collaboration	Search for exclusive Higgs and $ Z $ boson decays to $ \phi\gamma $ and $ \rho\gamma $ with the ATLAS detector	JHEP 07 (2018) 127	1712.02758
34	D. de Florian et al.	Handbook of LHC Higgs cross sections: 4. Deciphering the nature of the Higgs sector	CERN-2017-002-M	1610.07922
35	G. Isidori, A. V. Manohar, and M. Trott	Probing the nature of the Higgs-like boson via $ h \to v \mathcal{F} $ decays	PLB 728 (2014) 131	1305.0663
36	ATLAS Collaboration	Search for Higgs boson decays into a $ Z $ boson and a light hadronically decaying resonance using 13 TeV pp collision data from the ATLAS detector	Submitted to PRLett	2004.01678
37	G. F. Giudice and O. Lebedev	Higgs-dependent Yukawa couplings	PLB 665 (2008) 79	0804.1753
38	F. Bishara, J. Brod, P. Uttayarat, and J. Zupan	Nonstandard Yukawa couplings and Higgs portal dark matter	JHEP 01 (2016) 010	1504.04022
39	C. D. Froggatt and H. B. Nielsen	Hierarchy of quark masses, Cabibbo angles and CP violation	NPB 147 (1979) 277
40	M. Leurer, Y. Nir, and N. Seiberg	Mass matrix models: The sequel	NPB 420 (1994) 468	hep-ph/9310320
41	L. Randall and R. Sundrum	A large mass hierarchy from a small extra dimension	PRL 83 (1999) 3370	hep-ph/9905221
42	CMS Collaboration	Description and performance of track and primary-vertex reconstruction with the CMS tracker	JINST 9 (2014) P10009	CMS-TRK-11-001 1405.6569
43	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
44	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
45	CMS Collaboration	The CMS trigger system	JINST 12 (2017) P01020	CMS-TRG-12-001 1609.02366
46	CMS Collaboration	The CMS experiment at the CERN LHC	JINST 3 (2008) S08004	CMS-00-001
47	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
48	M. Cacciari, G. P. Salam, and G. Soyez	The anti-$ {k_{\mathrm{T}}} $ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
49	M. Cacciari, G. P. Salam, and G. Soyez	FastJet user manual	EPJC 72 (2012) 1896	1111.6097
50	P. Nason	A new method for combining NLO QCD with shower Monte Carlo algorithms	JHEP 11 (2004) 040	hep-ph/0409146
51	S. Frixione, P. Nason, and C. Oleari	Matching NLO QCD computations with parton shower simulations: the POWHEG method	JHEP 11 (2007) 070	0709.2092
52	S. Alioli, P. Nason, C. Oleari, and E. Re	NLO Higgs boson production via gluon fusion matched with shower in POWHEG	JHEP 04 (2009) 002	0812.0578
53	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
54	P. Nason and C. Oleari	NLO Higgs boson production via vector-boson fusion matched with shower in POWHEG	JHEP 02 (2010) 037	0911.5299
55	G. Luisoni, P. Nason, C. Oleari, and F. Tramontano	HW$ ^{\pm} $/HZ + 0 and 1 jet at NLO with the POWHEG BOX interfaced to GoSam and their merging within MiNLO	JHEP 10 (2013) 083	1306.2542
56	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
57	T. Sjostrand et al.	An introduction to PYTHIA 8.2	CPC 191 (2015) 159	1410.3012
58	NNPDF Collaboration	Parton distributions for the LHC run II	JHEP 04 (2015) 040	1410.8849
59	NNPDF Collaboration	Parton distributions from high-precision collider data	EPJC 77 (2017) 663	1706.00428
60	CMS Collaboration	Event generator tunes obtained from underlying event and multiparton scattering measurements	EPJC 76 (2016) 155	CMS-GEN-14-001 1512.00815
61	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
62	\GEANTfour Collaboration	GEANT4--a simulation toolkit	NIMA 506 (2003) 250
63	Particle Data Group, M. Tanabashi et al.	Review of particle physics	PRD 98 (2018) 030001
64	CMS Collaboration	Measurement of the inelastic proton-proton cross section at $ \sqrt{s}= $ 13 TeV	JHEP 07 (2018) 161	CMS-FSQ-15-005 1802.02613
65	CMS Collaboration	Measurements of inclusive $ \mathrm{W} $ and $ \mathrm{Z} $ cross sections in $ {\mathrm{p}}{\mathrm{p}} $ collisions at $ \sqrt{s}= $ 7 TeV	JHEP 01 (2011) 080	CMS-EWK-10-002 1012.2466
66	J. H. Broughton	Searches for Rare Exclusive Higgs Boson Decays to a Meson and an Associated Photon with the ATLAS Detector”	PhD thesis, Birmingham U.
67	R. D. Fisher	On the interpretation of $ \chi^2 $ from contingency tables, and the calculation of P	J. Royal Stat. Soc. 85 (1922) 87
68	CMS Collaboration	Search for narrow and broad dijet resonances in proton-proton collisions at $ \sqrt{s}= $ 13 TeV and constraints on dark matter mediators and other new particles	JHEP 08 (2018) 130	CMS-EXO-16-056 1806.00843
69	T. Junk	Confidence level computation for combining searches with small statistics	NIMA 434 (1999) 435	hep-ex/9902006
70	A. L. Read	Presentation of search results: The CL$ _{\text{s}} $ technique	JPG 28 (2002) 2693
71	The ATLAS Collaboration, The CMS Collaboration, The LHC Higgs Combination Group	Procedure for the LHC Higgs boson search combination in Summer 2011	CMS-NOTE-2011-005
72	G. Cowan, K. Cranmer, E. Gross, and O. Vitells	Asymptotic formulae for likelihood-based tests of new physics	EPJC 71 (2011) 1554	1007.1727
73	CMS Collaboration	CMS luminosity measurements for the 2016 data taking period	CMS-PAS-LUM-17-001	CMS-PAS-LUM-17-001
74	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
75	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

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