CMS logoCMS event Hgg
Compact Muon Solenoid
LHC, CERN

CMS-PAS-EXO-19-003
Search for dark matter produced in association with a Z boson in proton-proton collisions at $\sqrt{s}= $ 13 TeV
Abstract: A search for dark matter (DM) particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton-proton collision data at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2016-2018, corresponding to an integrated luminosity of 137 fb$^{-1}$. The search uses the decay channels $\mathrm{Z}\to\mathrm{e}\mathrm{e}$ and $\mathrm{Z}\to\mu\mu$. No significant excess of events is observed over the background expected from standard model processes. Limits are set on DM production in the context of simplified models with vector, axial-vector, scalar, and pseudoscalar mediators, as well as a two-Higgs-doublet model with an additional pseudoscalar mediator. The limits are also provided for spin-dependent and spin-independent scattering cross sections and are compared to those from direct-detection experiments. The results are also interpreted in the context of models of invisible Higgs boson decays, unparticles, and large extra dimensions.
Figures & Tables Summary References CMS Publications
Figures

png pdf
Figure 1:
Feynman diagrams illustrative of the BSM processes that produce a final state of a Z boson and missing transverse momentum: (upper left) simplified dark matter model for a spin-1 mediator, (upper right) 2HDM+a model, (lower left) invisible Higgs boson decays, and (lower right) unparticle / large extra dimensions. Here $\chi$ represents a DM particle, while H and a represent the additional neutral Higgs boson and pseudoscalar respectively. The dotted line represents either an unparticle or a graviton.

png pdf
Figure 1-a:
Feynman diagrams illustrative of the BSM processes that produce a final state of a Z boson and missing transverse momentum: (upper left) simplified dark matter model for a spin-1 mediator, (upper right) 2HDM+a model, (lower left) invisible Higgs boson decays, and (lower right) unparticle / large extra dimensions. Here $\chi$ represents a DM particle, while H and a represent the additional neutral Higgs boson and pseudoscalar respectively. The dotted line represents either an unparticle or a graviton.

png pdf
Figure 1-b:
Feynman diagrams illustrative of the BSM processes that produce a final state of a Z boson and missing transverse momentum: (upper left) simplified dark matter model for a spin-1 mediator, (upper right) 2HDM+a model, (lower left) invisible Higgs boson decays, and (lower right) unparticle / large extra dimensions. Here $\chi$ represents a DM particle, while H and a represent the additional neutral Higgs boson and pseudoscalar respectively. The dotted line represents either an unparticle or a graviton.

png pdf
Figure 1-c:
Feynman diagrams illustrative of the BSM processes that produce a final state of a Z boson and missing transverse momentum: (upper left) simplified dark matter model for a spin-1 mediator, (upper right) 2HDM+a model, (lower left) invisible Higgs boson decays, and (lower right) unparticle / large extra dimensions. Here $\chi$ represents a DM particle, while H and a represent the additional neutral Higgs boson and pseudoscalar respectively. The dotted line represents either an unparticle or a graviton.

png pdf
Figure 1-d:
Feynman diagrams illustrative of the BSM processes that produce a final state of a Z boson and missing transverse momentum: (upper left) simplified dark matter model for a spin-1 mediator, (upper right) 2HDM+a model, (lower left) invisible Higgs boson decays, and (lower right) unparticle / large extra dimensions. Here $\chi$ represents a DM particle, while H and a represent the additional neutral Higgs boson and pseudoscalar respectively. The dotted line represents either an unparticle or a graviton.

png pdf
Figure 2:
Emulated ${{p_{\mathrm {T}}} ^\text {miss}}$ distribution in data and simulation for the 3$\ell $ (left) and 4$\ell $ (right) CRs. The last bin also includes any events with emulated $ {{p_{\mathrm {T}}} ^\text {miss}} > $ 800 GeV Uncertainty bands correspond to the postfit combined statistical and systematic components.

png pdf
Figure 2-a:
Emulated ${{p_{\mathrm {T}}} ^\text {miss}}$ distribution in data and simulation for the 3$\ell $ (left) and 4$\ell $ (right) CRs. The last bin also includes any events with emulated $ {{p_{\mathrm {T}}} ^\text {miss}} > $ 800 GeV Uncertainty bands correspond to the postfit combined statistical and systematic components.

png pdf
Figure 2-b:
Emulated ${{p_{\mathrm {T}}} ^\text {miss}}$ distribution in data and simulation for the 3$\ell $ (left) and 4$\ell $ (right) CRs. The last bin also includes any events with emulated $ {{p_{\mathrm {T}}} ^\text {miss}} > $ 800 GeV Uncertainty bands correspond to the postfit combined statistical and systematic components.

png pdf
Figure 3:
The ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions for events in the signal region in the 0-jet (left) and 1-jet (right) categories. The last bin also includes any events with $ {{p_{\mathrm {T}}} ^\text {miss}} > $ 800 GeV. The uncertainty band includes both statistical and systematic components. The $\mathrm{Z} \mathrm{h} $ (invisible) signal normalization assumes SM production rates and the branching fraction $\mathcal {B}(\mathrm{h} \to $ invisible) $= $ 1.

png pdf
Figure 3-a:
The ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions for events in the signal region in the 0-jet (left) and 1-jet (right) categories. The last bin also includes any events with $ {{p_{\mathrm {T}}} ^\text {miss}} > $ 800 GeV. The uncertainty band includes both statistical and systematic components. The $\mathrm{Z} \mathrm{h} $ (invisible) signal normalization assumes SM production rates and the branching fraction $\mathcal {B}(\mathrm{h} \to $ invisible) $= $ 1.

png pdf
Figure 3-b:
The ${{p_{\mathrm {T}}} ^\text {miss}}$ distributions for events in the signal region in the 0-jet (left) and 1-jet (right) categories. The last bin also includes any events with $ {{p_{\mathrm {T}}} ^\text {miss}} > $ 800 GeV. The uncertainty band includes both statistical and systematic components. The $\mathrm{Z} \mathrm{h} $ (invisible) signal normalization assumes SM production rates and the branching fraction $\mathcal {B}(\mathrm{h} \to $ invisible) $= $ 1.

png pdf
Figure 4:
The $m_{\text T}$ distributions for events in the signal region in the 0-jet (left) and 1-jet (right) categories. The last bin also includes any events with $m_{\text T} > $ 1500 GeV. The uncertainty band includes both statistical and systematic components. The signal normalization assumes the expected values for $(m_\mathrm{H},m_{\text {A}}) = $ (1200,300) GeV within the 2HDM+a framework.

png pdf
Figure 4-a:
The $m_{\text T}$ distributions for events in the signal region in the 0-jet (left) and 1-jet (right) categories. The last bin also includes any events with $m_{\text T} > $ 1500 GeV. The uncertainty band includes both statistical and systematic components. The signal normalization assumes the expected values for $(m_\mathrm{H},m_{\text {A}}) = $ (1200,300) GeV within the 2HDM+a framework.

png pdf
Figure 4-b:
The $m_{\text T}$ distributions for events in the signal region in the 0-jet (left) and 1-jet (right) categories. The last bin also includes any events with $m_{\text T} > $ 1500 GeV. The uncertainty band includes both statistical and systematic components. The signal normalization assumes the expected values for $(m_\mathrm{H},m_{\text {A}}) = $ (1200,300) GeV within the 2HDM+a framework.

png pdf
Figure 5:
The 95% CL exclusion limits for the vector (left) and the axial-vector (right) simplified models. The limits are made as a function of both the mediator and DM particle masses. The coupling to quarks is fixed to $g_q=$ 0.25 and the coupling to DM is set to $g_\chi =$ 1.

png pdf
Figure 5-a:
The 95% CL exclusion limits for the vector (left) and the axial-vector (right) simplified models. The limits are made as a function of both the mediator and DM particle masses. The coupling to quarks is fixed to $g_q=$ 0.25 and the coupling to DM is set to $g_\chi =$ 1.

png pdf
Figure 5-b:
The 95% CL exclusion limits for the vector (left) and the axial-vector (right) simplified models. The limits are made as a function of both the mediator and DM particle masses. The coupling to quarks is fixed to $g_q=$ 0.25 and the coupling to DM is set to $g_\chi =$ 1.

png pdf
Figure 6:
The 90% CL DM nucleon cross section limits for simplified DM in the spin-independent (left) and spin-dependent (right) cases. Here, the coupling to quarks is set to $g_q=$ 0.25 and the coupling to DM is set to $g_\chi =$ 1. Limits from the XENON1T [89], LUX [90], PandaX-ll [91], CDMSLite [92], and DarkSide-50 [93] experiments are shown for the spin-independent case with vector couplings. Limits from the PICO-60 [94], PICO-2L [95], IceCube [96], and Super Kamiokande [97] experiments are shown for the spin-dependent case with axial-vector couplings.

png pdf
Figure 6-a:
The 90% CL DM nucleon cross section limits for simplified DM in the spin-independent (left) and spin-dependent (right) cases. Here, the coupling to quarks is set to $g_q=$ 0.25 and the coupling to DM is set to $g_\chi =$ 1. Limits from the XENON1T [89], LUX [90], PandaX-ll [91], CDMSLite [92], and DarkSide-50 [93] experiments are shown for the spin-independent case with vector couplings. Limits from the PICO-60 [94], PICO-2L [95], IceCube [96], and Super Kamiokande [97] experiments are shown for the spin-dependent case with axial-vector couplings.

png pdf
Figure 6-b:
The 90% CL DM nucleon cross section limits for simplified DM in the spin-independent (left) and spin-dependent (right) cases. Here, the coupling to quarks is set to $g_q=$ 0.25 and the coupling to DM is set to $g_\chi =$ 1. Limits from the XENON1T [89], LUX [90], PandaX-ll [91], CDMSLite [92], and DarkSide-50 [93] experiments are shown for the spin-independent case with vector couplings. Limits from the PICO-60 [94], PICO-2L [95], IceCube [96], and Super Kamiokande [97] experiments are shown for the spin-dependent case with axial-vector couplings.

png pdf
Figure 7:
The 95% CL cross section limits for simplified DM with scalar (left) and pseudoscalar (right) mediators. Here, the coupling to quarks is set to $g_q=$ 1, the coupling to DM is set to $g_\chi =$ 1 and the DM mass is $m_\chi = $ 1 GeV.

png pdf
Figure 7-a:
The 95% CL cross section limits for simplified DM with scalar (left) and pseudoscalar (right) mediators. Here, the coupling to quarks is set to $g_q=$ 1, the coupling to DM is set to $g_\chi =$ 1 and the DM mass is $m_\chi = $ 1 GeV.

png pdf
Figure 7-b:
The 95% CL cross section limits for simplified DM with scalar (left) and pseudoscalar (right) mediators. Here, the coupling to quarks is set to $g_q=$ 1, the coupling to DM is set to $g_\chi =$ 1 and the DM mass is $m_\chi = $ 1 GeV.

png pdf
Figure 8:
The 95% CL upper limits on the 2HDM+a model with the mixing angles set to $\tan(\beta)=$ 1 and $\sin(\theta)=$ 0.35 and with a DM particle mass of $m_{\chi} = $ 10 GeV. The limits are shown as a function of both mediator masses.

png pdf
Figure 9:
The 95% CL upper limits on unparticle+Z production cross section as a function of the scaling dimension $d_{\textsf U}$. These limits apply to a fixed value of the effective cutoff scale $\Lambda _{\textsf U} = $ 15 TeV and a fixed coupling $\lambda =$ 1.

png pdf
Figure 10:
The 95% CL cross section limits in the ADD scenario as a function of $M_{\text D}$ for different values of $n$.

png pdf
Figure 10-a:
The 95% CL cross section limits in the ADD scenario as a function of $M_{\text D}$ for different values of $n$.

png pdf
Figure 10-b:
The 95% CL cross section limits in the ADD scenario as a function of $M_{\text D}$ for different values of $n$.

png pdf
Figure 10-c:
The 95% CL cross section limits in the ADD scenario as a function of $M_{\text D}$ for different values of $n$.

png pdf
Figure 10-d:
The 95% CL cross section limits in the ADD scenario as a function of $M_{\text D}$ for different values of $n$.

png pdf
Figure 10-e:
The 95% CL cross section limits in the ADD scenario as a function of $M_{\text D}$ for different values of $n$.

png pdf
Figure 10-f:
The 95% CL cross section limits in the ADD scenario as a function of $M_{\text D}$ for different values of $n$.

png pdf
Figure 11:
The 95% CL expected and observed exclusion limits on $M_{\text D}$ as a function of the number of extra dimensions $n$.
Tables

png pdf
Table 1:
Summary of the kinematic selections for the signal region.

png pdf
Table 2:
Summary of impact of the systematic uncertainties considered in the $\mathrm{Z} \mathrm{h} $ (invisible) model assuming $\mathcal {B}(\mathrm{h} \to $ invisible) $= $ 1 (signal) and $\mathcal {B}(\mathrm{h} \to $ invisible) $= $ 0 (no signal). Here, lepton measurement refers to the combined trigger, lepton reconstruction and identification efficiencies, and the lepton momentum and electron energy scale systematics.

png pdf
Table 3:
Observed number of events, post-fit background estimates in the signal regions. The reported uncertainty represents the sum in quadrature of the statistical and systematic uncertainties.

png pdf
Table 4:
Expected yields and the product of acceptance and efficiency for several models used in the analysis. The quoted values correspond to the $\mathrm{Z} $ to $\ell \ell $ decays. The reported uncertainty represents the sum in quadrature of the statistical and systematic uncertainties.

png pdf
Table 5:
Observed and expected 95% CL limits on parameters for the simplified DM model with both vector and axial vector mediators, invisible decays of the Higgs boson, two-Higgs doublet model, large extra dimensions in the ADD scenario, and unparticle model. For the scalar/pseudoscalar the limits are dependent on the mediator mass so the lowest values for the ratio of observed to theoretical cross sections are presented.
Summary
Events with a Z boson recoiling against missing transverse momentum in proton-proton collisions at the LHC were used to search for physics beyond the standard model. The results are interpreted in the context of several different models of the coupling mechanism between dark matter and ordinary matter: simplified models of dark matter with vector, axial-vector, scalar, and pseudoscalar mediators, invisible decays of a standard-model-like Higgs boson, and a two-Higgs double model with an extra pseudoscalar. Outside of the context of dark matter, models that invoke large extra dimensions or propose the production of unparticles could contribute to the same final signature and are also considered. The observed limits on the production cross sections are used to constrain parameters of each of these models. The search utilizes the entire Run 2 dataset of the CMS experiment, corresponding to an integrated luminosity of 137 fb$^{-1}$ at $ \sqrt{s} = $ 13 TeV. No evidence of physics beyond the Standard Model is observed. Comparing to the previous results in this channel with 35.9 fb$^{-1}$ for CMS [3] and for ATLAS [4], the exclusion limits for simplified dark matter mediators, gravitons and unparticles are significantly extended. For the case of a standard-model-like Higgs Boson, an upper limit of 29% is set for the branching fraction to fully invisible decays at 95% confidence level. Results for the 2HDM+a model are presented in this final state for the first time by CMS and probe masses of the pseudoscalar mediator up to 440 GeV and of the heavy Higgs scalar up to 1200 GeV when the other model parameters are set to specific benchmark values.
References
1 G. Bertone and D. Hooper History of dark matter Rev. Mod. Phys. 90 (2018) 045002 1605.04909
2 Planck Collaboration Planck 2018 results. I. Overview and the cosmological legacy of Planck 1807.06205
3 CMS Collaboration Search for new physics in events with a leptonically decaying Z boson and a large transverse momentum imbalance in proton-proton collisions at $ \sqrt{s} = $ 13 TeV EPJC 78 (2018) 291 CMS-EXO-16-052
1711.00431
4 ATLAS Collaboration Search for an invisibly decaying Higgs boson or dark matter candidates produced in association with a $ Z $ boson in pp collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector PLB 776 (2018) 318 1708.09624
5 ATLAS Collaboration Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector JHEP 01 (2018) 126 1711.03301
6 CMS Collaboration Search for new physics in final states with an energetic jet or a hadronically decaying $ W $ or $ Z $ boson and transverse momentum imbalance at $ \sqrt{s}=$ 13 TeV PRD 97 (2018) 092005 CMS-EXO-16-048
1712.02345
7 ATLAS Collaboration Search for dark matter at $ \sqrt{s}= $ 13 TeV in final states containing an energetic photon and large missing transverse momentum with the ATLAS detector EPJC 77 (2017) 393 1704.03848
8 CMS Collaboration Search for new physics in the monophoton final state in proton-proton collisions at $ \sqrt{s}= $ 13 TeV JHEP 10 (2017) 073 CMS-EXO-16-039
1706.03794
9 ATLAS Collaboration Search for dark matter produced in association with bottom or top quarks in $ \sqrt{s}= $ 13 TeV pp collisions with the ATLAS detector EPJC 78 (2018) 18 1710.11412
10 CMS Collaboration Search for dark matter in events with energetic, hadronically decaying top quarks and missing transverse momentum at $ \sqrt{s}= $ 13 TeV JHEP 06 (2018) 027 CMS-EXO-16-051
1801.08427
11 ATLAS Collaboration Search for dark matter in events with a hadronically decaying vector boson and missing transverse momentum in pp collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector JHEP 10 (2018) 180 1807.11471
12 ATLAS Collaboration Search for Dark Matter in Events with Missing Transverse Momentum and a Higgs Boson Decaying to Two Photons in pp Collisions at $ \sqrt{s}= $ 8 TeV with the ATLAS Detector PRL 115 (2015) 131801 1506.01081
13 ATLAS Collaboration Search for dark matter produced in association with a Higgs boson decaying to two bottom quarks in pp collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector PRD 93 (2016) 072007 1510.06218
14 ATLAS Collaboration Search for dark matter in association with a Higgs boson decaying to $ b $-quarks in pp collisions at $ \sqrt s= $ 13 TeV with the ATLAS detector PLB 765 (2017) 11 1609.04572
15 CMS Collaboration Search for associated production of dark matter with a Higgs boson decaying to $ \mathrm{b}\overline{\mathrm{b}} $ or $ \gamma \gamma $ at $ \sqrt{s}= $ 13 TeV JHEP 10 (2017) 180 CMS-EXO-16-012
1703.05236
16 ATLAS Collaboration Search for dark matter in association with a Higgs boson decaying to two photons at $ \sqrt{s} = $ 13 TeV with the ATLAS detector PRD 96 (2017) 112004 1706.03948
17 ATLAS Collaboration Search for dark matter produced in association with a Higgs boson decaying to $ b\bar b $ using 36 fb$ ^{-1} $ of pp collisions at $ \sqrt s= $ 13 tev with the ATLAS detector PRL 119 (2017) 181804 1707.01302
18 CMS Collaboration Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos and b quarks at $ \sqrt{s}= $ 13 TeV JHEP 11 (2018) 172 CMS-B2G-17-004
1807.02826
19 CMS Collaboration Search for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks in proton-proton collisions at $ \sqrt{s}=$ 13 TeV EPJC 79 (2019) 280 CMS-EXO-16-050
1811.06562
20 CMS Collaboration Search for dark matter produced in association with a Higgs boson decaying to $ \gamma\gamma $ or $ \tau^+\tau^- $ at $ \sqrt{s} = $ 13 TeV JHEP 09 (2018) 046 CMS-EXO-16-055
1806.04771
21 CMS Collaboration Search for dark matter particles produced in association with a Higgs boson in proton-proton collisions at $ \sqrt{s} = $ 13 TeV JHEP 03 (2020) 025 CMS-EXO-18-011
1908.01713
22 D. Abercrombie et al. Dark Matter Benchmark Models for Early LHC Run-2 Searches: Report of the ATLAS/CMS Dark Matter Forum Phys. Dark Univ. 27 (2020) 100371 1507.00966
23 G. Busoni et al. Recommendations on presenting LHC searches for missing transverse energy signals using simplified $ s $-channel models of dark matter Phys. Dark Univ. 27 (2020) 100365 1603.04156
24 M. Bauer, U. Haisch, and F. Kahlhoefer Simplified dark matter models with two Higgs doublets: I. Pseudoscalar mediators JHEP 05 (2017) 138 1701.07427
25 LHC Dark Matter Working Group Collaboration LHC Dark Matter Working Group: next-generation spin-0 dark matter models Phys. Dark Univ. 27 (2020) 100351 1810.09420
26 S. Baek, P. Ko, W.-I. Park, and E. Senaha Higgs portal vector dark matter : revisited JHEP 05 (2013) 036 1212.2131
27 A. Djouadi, O. Lebedev, Y. Mambrini, and J. Quevillon Implications of LHC searches for Higgs--portal dark matter PLB 709 (2012) 65 1112.3299
28 A. Djouadi, A. Falkowski, Y. Mambrini, and J. Quevillon Direct Detection of Higgs-Portal Dark Matter at the LHC EPJC 73 (2013) 2455 1205.3169
29 G. Arcadi, A. Djouadi, and M. Raidal Dark matter through the higgs portal Physics Reports 842 (2020) 1, . Dark Matter through the Higgs portal
30 G. Belanger et al. The MSSM invisible Higgs in the light of dark matter and g-2 PLB 519 (2001) 93 hep-ph/0106275
31 H. Georgi Unparticle physics PRL 98 (2007) 221601 hep-ph/0703260
32 H. Georgi Another odd thing about unparticle physics PLB 650 (2007) 275 0704.2457
33 Z. Kang Upgrading sterile neutrino dark matter to FI$ m $P using scale invariance EPJC 75 (2015) 471 1411.2773
34 M. Rinaldi, G. Cognola, L. Vanzo, and S. Zerbini Inflation in scale-invariant theories of gravity PRD 91 (2015) 123527 1410.0631
35 H. Cheng The possible existence of Weyl's vector meson PRL 61 (1988) 2182
36 T. Banks and A. Zaks On the phase structure of vector-like gauge theories with massless fermions NPB 196 (1982) 189
37 K. Cheung, W.-Y. Keung, and T.-C. Yuan Collider signals of unparticle physics PRL 99 (2007) 051803 0704.2588
38 N. Arkani-Hamed, S. Dimopoulos, and G. R. Dvali The Hierarchy problem and new dimensions at a millimeter PLB 429 (1998) 263 hep-ph/9803315
39 T. Han, J. D. Lykken, and R. Zhang On Kaluza-Klein states from large extra dimensions PRD 59 (1999) 105006
40 CMS Collaboration The CMS trigger system JINST 12 (2017) P01020 CMS-TRG-12-001
1609.02366
41 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004 CMS-00-001
42 P. Nason A new method for combining NLO QCD with shower Monte Carlo algorithms JHEP 11 (2004) 040 hep-ph/0409146
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 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
45 S. Frixione, P. Nason, and G. Ridolfi A Positive-weight next-to-leading-order Monte Carlo for heavy flavour hadroproduction JHEP 09 (2007) 126 0707.3088
46 E. Bagnaschi, G. Degrassi, P. Slavich, and A. Vicini Higgs production via gluon fusion in the POWHEG approach in the SM and in the MSSM JHEP 02 (2012) 088 1111.2854
47 LHC Higgs Cross Section Working Group Collaboration Handbook of LHC Higgs Cross Sections: 3. Higgs Properties 1307.1347
48 LHC Higgs Cross Section Working Group Collaboration Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector 1610.07922
49 O. Mattelaer and E. Vryonidou Dark matter production through loop-induced processes at the LHC: the s-channel mediator case EPJC 75 (2015) 436 1508.00564
50 M. Neubert, J. Wang, and C. Zhang Higher-Order QCD Predictions for Dark Matter Production in Mono-$ Z $ Searches at the LHC JHEP 02 (2016) 082 1509.05785
51 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
52 R. Frederix and S. Frixione Merging meets matching in MC@NLO JHEP 12 (2012) 061 1209.6215
53 P. Artoisenet, R. Frederix, O. Mattelaer, and R. Rietkerk Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations JHEP 03 (2013) 015 1212.3460
54 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
55 T. Sjostrand et al. An Introduction to PYTHIA 8.2 CPC 191 (2015) 159 1410.3012
56 S. Ask Simulation of Z plus Graviton/Unparticle Production at the LHC EPJC 60 (2009) 509 0809.4750
57 NNPDF Collaboration Parton distributions from high-precision collider data EPJC 77 (2017) 663 1706.00428
58 CMS Collaboration Event generator tunes obtained from underlying event and multiparton scattering measurements EPJC 76 (2016) 155 CMS-GEN-14-001
1512.00815
59 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
60 \GEANTfour Collaboration GEANT4 --- a simulation toolkit NIMA 506 (2003) 250
61 CMS Collaboration Pileup mitigation at CMS in 13 TeV data Submitted to JINST CMS-JME-18-001
2003.00503
62 CMS Collaboration Particle-flow reconstruction and global event description with the CMS detector JINST 12 (2017) P10003 CMS-PRF-14-001
1706.04965
63 M. Cacciari, G. P. Salam, and G. Soyez The anti-$ k_t $ jet clustering algorithm JHEP 04 (2008) 063 0802.1189
64 M. Cacciari, G. P. Salam, and G. Soyez FastJet user manual EPJC 72 (2012) 1896 1111.6097
65 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
66 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
67 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
68 CMS Collaboration Jet algorithms performance in 13 tev data CMS-PAS-JME-16-003 CMS-PAS-JME-16-003
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 reconstruction and identification of $ \tau $ leptons decaying to hadrons and $ \nu_\tau $ in pp collisions at $ \sqrt{s}= $ 13 TeV JINST 13 (2018) P10005 CMS-TAU-16-003
1809.02816
71 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
72 Particle Data Group, M. Tanabashi et al. Review of particle physics PRD 98 (2018) 030001
73 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
74 CMS Collaboration CMS luminosity measurement for the 2016 data-taking period CMS-PAS-LUM-15-001 CMS-PAS-LUM-15-001
75 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
76 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
77 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
78 CMS Collaboration Measurements of differential Z boson production cross sections in proton-proton collisions at $ \sqrt{s} = $ 13 TeV JHEP 12 (2019) 061 CMS-SMP-17-010
1909.04133
79 ATLAS Collaboration Measurement of the inelastic proton-proton cross section at $ \sqrt{s} = $ 13 TeV with the ATLAS detector at the LHC PRL 117 (2016) 182002 1606.02625
80 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
81 J. Rojo et al. The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II JPG 42 (2015) 103103 1507.00556
82 J. Butterworth et al. PDF4LHC recommendations for LHC Run II JPG 43 (2016) 023001 1510.03865
83 A. Accardi et al. A Critical Appraisal and Evaluation of Modern PDFs EPJC 76 (2016) 471 1603.08906
84 A. Bierweiler, T. Kasprzik, and J. H. Kuhn Vector-boson pair production at the LHC to $ \mathcal{O}(\alpha^3) $ accuracy JHEP 12 (2013) 071 1305.5402
85 S. Gieseke, T. Kasprzik, and J. H. Kahn Vector-boson pair production and electroweak corrections in HERWIG++ EPJC 74 (2014) 2988 1401.3964
86 A. L. Read Presentation of search results: the CLs technique JPG: Nucl. Part. Phys. 28 (2002) 2693
87 T. Junk Confidence level computation for combining searches with small statistics NIMA 434 (1999) 435
88 L. Demortier P values and nuisance parameters in Statistical issues for LHC physics. Proceedings, Workshop, PHYSTAT-LHC, Geneva, Switzerland, June 27-29, 2007, p. 23 2008
89 XENON Collaboration Dark Matter Search Results from a One Ton-Year Exposure of XENON1T PRL 121 (2018) 111302 1805.12562
90 LUX Collaboration Results from a search for dark matter in the complete LUX exposure PRL 118 (2017) 021303 1608.07648
91 PandaX-II Collaboration Dark Matter Results From 54-Ton-Day Exposure of PandaX-II Experiment PRL 119 (2017) 181302 1708.06917
92 SuperCDMS Collaboration Search for Low-Mass Dark Matter with CDMSlite Using a Profile Likelihood Fit PRD 99 (2019) 062001 1808.09098
93 DarkSide Collaboration Low-Mass Dark Matter Search with the DarkSide-50 Experiment PRL 121 (2018) 081307 1802.06994
94 PICO Collaboration Dark Matter Search Results from the Complete Exposure of the PICO-60 C$ _3 $F$ _8 $ Bubble Chamber PRD 100 (2019) 022001 1902.04031
95 PICO Collaboration Improved dark matter search results from PICO-2L Run 2 PRD 93 (2016) 061101 1601.03729
96 IceCube Collaboration Improved limits on dark matter annihilation in the Sun with the 79-string IceCube detector and implications for supersymmetry JCAP 04 (2016) 022 1601.00653
97 Super-Kamiokande Collaboration Search for neutrinos from annihilation of captured low-mass dark matter particles in the Sun by Super-Kamiokande PRL 114 (2015) 141301 1503.04858
98 ATLAS Collaboration Constraints on mediator-based dark matter and scalar dark energy models using $ \sqrt{s} = $ 13 TeV pp collision data collected by the ATLAS detector JHEP 05 (2019) 142 1903.01400
99 R. V. Harlander, J. Klappert, S. Liebler, and L. Simon vh@nnlo-v2: New physics in Higgs Strahlung JHEP 05 (2018) 089 1802.04817
100 CMS Collaboration Search for invisible decays of a Higgs boson produced through vector boson fusion in proton-proton collisions at $ \sqrt{s} = $ 13 TeV PLB 793 (2019) 520 CMS-HIG-17-023
1809.05937
101 ATLAS Collaboration Combination of searches for invisible Higgs boson decays with the ATLAS experiment PRL 122 (2019) 231801 1904.05105
Compact Muon Solenoid
LHC, CERN