CMS-EXO-17-005

CMS-EXO-17-005 ; CERN-EP-2017-301
Search for Z $\gamma$ resonances using leptonic and hadronic final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV
CMS Collaboration
9 December 2017
JHEP 09 (2018) 148
Abstract: A search is presented for resonances decaying to a Z boson and a photon. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb $^{-1}$ , and collected with the CMS detector at the LHC in 2016. Two decay modes of the Z boson are investigated. In the leptonic channels, the Z boson candidates are reconstructed using electron or muon pairs. In the hadronic channels, they are identified using a large-radius jet, containing either light-quark or b quark decay products of the Z boson, via jet substructure and advanced b quark tagging techniques. The results from these channels are combined and interpreted in terms of upper limits on the product of the production cross section and the branching fraction to Z $\gamma$ for narrow and broad spin-0 resonances with masses between 0.35 and 4.0 TeV, providing thereby the most stringent limits on such resonances.
Links: e-print arXiv:1712.03143 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Observed ${m_{{\mathrm {Z}} \gamma}}$ invariant mass spectra in the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ (left) and ${{{\mu}} {{\mu}}\gamma}$ (right) channels. The best fits to the background-only hypotheses are represented by the red lines, with their 68% CL uncertainty bands given by the gray shadings. Several narrow and broad signal benchmarks with arbitrary normalization are shown on top of the background prediction with the dashed lines. The lower panels show the difference between the data and the fits, divided by the uncertainty, which includes the statistical uncertainties in the data and the fit. For bins with a small number of entries, the error bars correspond to the Garwood confidence intervals [77].
png pdf	Figure 1-a: Observed ${m_{{\mathrm {Z}} \gamma}}$ invariant mass spectrum in the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ channel. The best fits to the background-only hypotheses are represented by the red lines, with their 68% CL uncertainty bands given by the gray shadings. Several narrow and broad signal benchmarks with arbitrary normalization are shown on top of the background prediction with the dashed lines. The lower panel shows the difference between the data and the fits, divided by the uncertainty, which includes the statistical uncertainties in the data and the fit. For bins with a small number of entries, the error bars correspond to the Garwood confidence intervals [77].
png pdf	Figure 1-b: Observed ${m_{{\mathrm {Z}} \gamma}}$ invariant mass spectrum in the ${{{\mu}} {{\mu}}\gamma}$ channel. The best fits to the background-only hypotheses are represented by the red lines, with their 68% CL uncertainty bands given by the gray shadings. Several narrow and broad signal benchmarks with arbitrary normalization are shown on top of the background prediction with the dashed lines. The lower panel shows the difference between the data and the fits, divided by the uncertainty, which includes the statistical uncertainties in the data and the fit. For bins with a small number of entries, the error bars correspond to the Garwood confidence intervals [77].
png pdf	Figure 2: Observed ${m_{{\mathrm {Z}} \gamma}}$ invariant mass spectra in the ${\mathrm {J}\gamma}$ channel in the b-tagged (left), $\tau _{21}$ -tagged (center), and untagged (right) categories. The best fits to the background-only hypotheses are represented by the red lines, with their 68% CL uncertainty bands given by the gray shadings. Several narrow and broad signal benchmarks with arbitrary normalization are shown on top of the background prediction with the dashed lines. The lower panels show the difference between the data and the fits, divided by the uncertainty, which includes the statistical uncertainties in the data and the fit. For bins with a small number of entries, the error bars correspond to the Garwood confidence intervals [77].
png pdf	Figure 2-a: Observed ${m_{{\mathrm {Z}} \gamma}}$ invariant mass spectrum in the ${\mathrm {J}\gamma}$ channel in the b-tagged category. The best fits to the background-only hypotheses are represented by the red lines, with their 68% CL uncertainty bands given by the gray shadings. Several narrow and broad signal benchmarks with arbitrary normalization are shown on top of the background prediction with the dashed lines. The lower panel shows the difference between the data and the fits, divided by the uncertainty, which includes the statistical uncertainties in the data and the fit. For bins with a small number of entries, the error bars correspond to the Garwood confidence intervals [77].
png pdf	Figure 2-b: Observed ${m_{{\mathrm {Z}} \gamma}}$ invariant mass spectrum in the ${\mathrm {J}\gamma}$ channel in the $\tau _{21}$ -tagged category. The best fits to the background-only hypotheses are represented by the red lines, with their 68% CL uncertainty bands given by the gray shadings. Several narrow and broad signal benchmarks with arbitrary normalization are shown on top of the background prediction with the dashed lines. The lower panel shows the difference between the data and the fits, divided by the uncertainty, which includes the statistical uncertainties in the data and the fit. For bins with a small number of entries, the error bars correspond to the Garwood confidence intervals [77].
png pdf	Figure 2-c: Observed ${m_{{\mathrm {Z}} \gamma}}$ invariant mass spectrum in the ${\mathrm {J}\gamma}$ channel in the untagged category. The best fits to the background-only hypotheses are represented by the red lines, with their 68% CL uncertainty bands given by the gray shadings. Several narrow and broad signal benchmarks with arbitrary normalization are shown on top of the background prediction with the dashed lines. The lower panel shows the difference between the data and the fits, divided by the uncertainty, which includes the statistical uncertainties in the data and the fit. For bins with a small number of entries, the error bars correspond to the Garwood confidence intervals [77].
png pdf	Figure 3: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})\,\mathcal {B}({\mathrm {Z}} \to \ell \ell {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ for the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ (left column) and ${{{\mu}} {{\mu}}\gamma}$ (right column) channels, and for narrow (upper row) and broad (lower row) spin-0 resonances. The green and yellow shaded bands correspond to respective 68 and 95% CL ranges in the expected limits for the background-only hypothesis.
png pdf	Figure 3-a: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})\,\mathcal {B}({\mathrm {Z}} \to \ell \ell {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ for the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ channel, and for a narrow spin-0 resonance. The green and yellow shaded bands correspond to respective 68 and 95% CL ranges in the expected limits for the background-only hypothesis.
png pdf	Figure 3-b: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})\,\mathcal {B}({\mathrm {Z}} \to \ell \ell {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ for the ${{{\mu}} {{\mu}}\gamma}$ channel, and for a narrow spin-0 resonance. The green and yellow shaded bands correspond to respective 68 and 95% CL ranges in the expected limits for the background-only hypothesis.
png pdf	Figure 3-c: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})\,\mathcal {B}({\mathrm {Z}} \to \ell \ell {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ for the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ channel, and for a broad spin-0 resonance. The green and yellow shaded bands correspond to respective 68 and 95% CL ranges in the expected limits for the background-only hypothesis.
png pdf	Figure 3-d: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})\,\mathcal {B}({\mathrm {Z}} \to \ell \ell {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ for the ${{{\mu}} {{\mu}}\gamma}$ channel, and for a broad spin-0 resonance. The green and yellow shaded bands correspond to respective 68 and 95% CL ranges in the expected limits for the background-only hypothesis.
png pdf	Figure 4: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ as a function of signal mass $m_\mathrm {X}$ , together with the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis, for the combination of the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ and ${{{\mu}} {{\mu}}\gamma}$ channels for (left) narrow and (right) broad spin-0 resonances.
png pdf	Figure 4-a: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ as a function of signal mass $m_\mathrm {X}$ , together with the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis, for the combination of the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ and ${{{\mu}} {{\mu}}\gamma}$ channels for narrow spin-0 resonances.
png pdf	Figure 4-b: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ as a function of signal mass $m_\mathrm {X}$ , together with the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis, for the combination of the ${{\mathrm {e}} {\mathrm {e}}\gamma}$ and ${{{\mu}} {{\mu}}\gamma}$ channels for broad spin-0 resonances.
png pdf	Figure 5: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for the b-tagged (left column), $\tau _{21}$ -tagged (middle column), and untagged (right column) categories, and for narrow (upper row) and broad (lower row) spin-0 resonances. The colored bands correspond to the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis.
png pdf	Figure 5-a: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for the b-tagged category, and for narrow spin-0 resonances. The colored bands correspond to the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis.
png pdf	Figure 5-b: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for the $\tau _{21}$ -tagged category, and for narrow spin-0 resonances. The colored bands correspond to the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis.
png pdf	Figure 5-c: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for the untagged category, and for narrow spin-0 resonances. The colored bands correspond to the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis.
png pdf	Figure 5-d: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for the b-tagged category, and for broad spin-0 resonances. The colored bands correspond to the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis.
png pdf	Figure 5-e: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for the $\tau _{21}$ -tagged category, and for broad spin-0 resonances. The colored bands correspond to the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis.
png pdf	Figure 5-f: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for the untagged category, and for broad spin-0 resonances. The colored bands correspond to the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis.
png pdf	Figure 6: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ as a function of signal mass $m_\mathrm {X}$ , together with the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis, for the combination of the b-tagged, $\tau _{21}$ -tagged, and untagged categories for (left) narrow and (right) broad spin-0 resonances.
png pdf	Figure 6-a: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ as a function of signal mass $m_\mathrm {X}$ , together with the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis, for the combination of the b-tagged, $\tau _{21}$ -tagged, and untagged categories for narrow spin-0 resonances.
png pdf	Figure 6-b: Observed (solid) and expected (dashed) 95% CL upper limits on $\sigma (\mathrm {X}\to {\mathrm {Z}} {\gamma})$ as a function of signal mass $m_\mathrm {X}$ , together with the 68% (green) and 95% (yellow) CL ranges of the expected limit for the background-only hypothesis, for the combination of the b-tagged, $\tau _{21}$ -tagged, and untagged categories for broad spin-0 resonances.
png pdf	Figure 7: Observed and expected limits on the product of the production cross section and branching fraction $\mathcal {B}(\mathrm {X} \to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for (left) narrow and (right) broad spin-0 resonances, obtained from the combination of the leptonic and hadronic decay channels.
png pdf	Figure 7-a: Observed and expected limits on the product of the production cross section and branching fraction $\mathcal {B}(\mathrm {X} \to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for narrow spin-0 resonances, obtained from the combination of the leptonic and hadronic decay channels.
png pdf	Figure 7-b: Observed and expected limits on the product of the production cross section and branching fraction $\mathcal {B}(\mathrm {X} \to {\mathrm {Z}} {\gamma})$ , as a function of signal mass $m_\mathrm {X}$ , for broad spin-0 resonances, obtained from the combination of the leptonic and hadronic decay channels.

Tables
png pdf	Table 1: Summary of the systematic uncertainties in the signal yield (upper part of the table) or shape (lower part of the table). A dash indicates that the uncertainty does not apply.

Summary

A search is presented for resonances decaying to a Z boson and a photon. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb

$^{-1}$ , collected with the CMS detector at the LHC in 2016. Two decay modes of the Z boson are investigated. In the leptonic channels, the Z boson candidates are reconstructed using electron or muon pairs. In the hadronic channels, they are identified using a large-radius jet, containing either light-quark or b quark decay products of the Z boson, via jet substructure and advanced b tagging techniques. The results from these channels are combined and interpreted in terms of upper limits on the product of the production cross section and the branching fraction to Z

$\gamma$ for narrow (broad) spin-0 resonances with masses between 0.35 and 4.0 TeV, ranging from 50 (100) to 0.3 (1.5) fb. These are the most stringent limits on such resonances to date.

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	CMS Collaboration	Search for massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at $\sqrt{s} =$ 8 TeV	JHEP 08 (2014) 173	CMS-EXO-12-024 1405.1994
5	CMS Collaboration	Search for massive resonances decaying into pairs of boosted bosons in semi-leptonic final states at $\sqrt{s} =$ 8 TeV	JHEP 08 (2014) 174	CMS-EXO-13-009 1405.3447
6	ATLAS Collaboration	Combination of searches for WW, WZ, and ZZ resonances in pp collisions at $\sqrt{s} =$ 8 TeV with the ATLAS detector	PLB 755 (2016) 285	1512.05099
7	ATLAS Collaboration	Searches for heavy diboson resonances in pp collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector	JHEP 09 (2016) 173	1606.04833
8	CMS Collaboration	Search for massive resonances decaying into WW, WZ or ZZ bosons in proton-proton collisions at $\sqrt{s} =$ 13 TeV	JHEP 03 (2017) 162	CMS-B2G-16-004 1612.09159
9	CMS Collaboration	Search for charged higgs bosons produced via vector boson fusion and decaying into a pair of $W$ and $Z$ bosons using $pp$ collisions at $\sqrt{s}=$ 13 TeV	PRL 119 (2017) 141802	CMS-HIG-16-027 1705.02942
10	CMS Collaboration	Combination of searches for heavy resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton?proton collisions at $\sqrt{s}=$ 8 and 13 TeV	PLB 774 (2017) 533	CMS-B2G-16-007 1705.09171
11	ATLAS Collaboration	Search for diboson resonances with boson-tagged jets in $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector	PLB 777 (2018) 91	1708.04445
12	ATLAS Collaboration	Searches for heavy $ZZ$ and $ZW$ resonances in the $\ell\ell qq$ and $\nu\nu qq$ final states in $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector	JHEP 03 (2018) 009	1708.09638
13	ATLAS Collaboration	Search for $WW/WZ$ resonance production in $\ell \nu qq$ final states in $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector	JHEP 03 (2018) 042	1710.07235
14	ATLAS Collaboration	Search for heavy resonances decaying into $WW$ in the $e\nu\mu\nu$ final state in $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector	EPJC 78 (2018) 24	1710.01123
15	CMS Collaboration	Search for ZZ resonances in the 2 $\ell 2 \nu$ final state in proton-proton collisions at 13 TeV	JHEP 03 (2018) 003	CMS-B2G-16-023 1711.04370
16	CMS Collaboration	Search for a massive resonance decaying into a Higgs boson and a W or Z boson in hadronic final states in proton-proton collisions at $\sqrt{s}=$ 8 TeV	JHEP 02 (2016) 145	CMS-EXO-14-009 1506.01443
17	CMS Collaboration	Search for massive WH resonances decaying into the $\ell \nu \mathrm{b} \overline{\mathrm{b}}$ final state at $\sqrt{s}=$ 8 TeV	EPJC 76 (2016) 237	CMS-EXO-14-010 1601.06431
18	ATLAS Collaboration	Search for new resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the $\ell^+ \ell^-\text{b}\bar{\text{b}}$ , $\ell \nu\text{b}\bar{\text{b}}$ , and $\nu\bar{\nu}\text{b}\bar{\text{b}}$ channels with pp collisions at $\sqrt s =$ 13 TeV with the ATLAS detector	PLB 765 (2017) 32	1607.05621
19	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	PLB 768 (2017) 137	CMS-B2G-16-003 1610.08066
20	CMS Collaboration	Search for heavy resonances that decay into a vector boson and a Higgs boson in hadronic final states at $\sqrt{s} =$ 13 TeV	EPJC 77 (2017) 636	CMS-B2G-17-002 1707.01303
21	ATLAS Collaboration	Search for heavy resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the $q\bar{q}^{(\prime)}b\bar{b}$ final state in $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector	PLB 774 (2017) 494	1707.06958
22	L. D. Landau	On the angular momentum of a system of two photons	Dokl. Akad. Nauk Ser. Fiz. 60 (1948) 207
23	C.-N. Yang	Selection rules for the dematerialization of a particle into two photons	PR77 (1950) 242
24	E. Eichten and K. Lane	Low-scale technicolor at the Tevatron and LHC	PLB 669 (2008) 235	0706.2339
25	A. Freitas and P. Schwaller	Multi-photon signals from composite models at LHC	JHEP 01 (2011) 022	1010.2528
26	R. Barbieri and R. Torre	Signals of single particle production at the earliest LHC	PLB 695 (2011) 259	1008.5302
27	I. Low, J. Lykken, and G. Shaughnessy	Singlet scalars as Higgs imposters at the Large Hadron Collider	PRD 84 (2011) 035027	1105.4587
28	H. Davoudiasl, J. L. Hewett, and T. G. Rizzo	Experimental probes of localized gravity: On and off the wall	PRD 63 (2001) 075004	hep-ph/0006041
29	B. C. Allanach, J. P. Skittrall, and K. Sridhar	Z boson decay to photon plus Kaluza-Klein graviton in large extra dimensions	JHEP 11 (2007) 089	0705.1953
30	ATLAS Collaboration	Searches for the $Z\gamma$ decay mode of the Higgs boson and for new high-mass resonances in $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector	JHEP 10 (2017) 112	1708.00212
31	ATLAS Collaboration	Search for heavy resonances decaying to a $\mathrm{Z}$ boson and a photon in pp collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector	PLB 764 (2017) 11	1607.06363
32	CMS Collaboration	Search for high-mass $\mathrm{Z}\gamma$ resonances in proton-proton collisions at $\sqrt{s}=$ 8 and 13 TeV using jet substructure techniques	PLB 772 (2017) 363	CMS-EXO-16-025 1612.09516
33	L3 Collaboration	Search for anomalous couplings in the Higgs sector at LEP	PLB 589 (2004) 89	hep-ex/0403037
34	D0 Collaboration	Search for particles decaying into a Z boson and a photon in ${\rm p\bar{p}}$ collisions at $\sqrt{s} =$ 1.96 TeV	PLB 641 (2006) 415	hep-ex/0605064
35	D0 Collaboration	Search for a scalar or vector particle decaying into $\mathrm{Z} \gamma$ in $\text{p} \bar{\text{p}}$ collisions at $\sqrt{s}=$ 1.96 TeV	PLB 671 (2009) 349	0806.0611
36	ATLAS Collaboration	Measurements of $\mathrm{W}\gamma$ and $\mathrm{Z}\gamma$ production in pp collisions at $\sqrt{s}=$ 7 TeV with the ATLAS detector at the LHC	PRD 87 (2013) 112003	1302.1283
37	ATLAS Collaboration	Search for new resonances in $\mathrm{W}\gamma$ and $\mathrm{Z}\gamma$ final states in pp collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector	PLB 738 (2014) 428	1407.8150
38	CMS Collaboration	Search for high-mass Z $\gamma$ resonances in $\mathrm{e}^+\mathrm{e}^-\gamma$ and $\mu^+\mu^-\gamma$ final states in proton-proton collisions at $\sqrt{s}=$ 8 and 13 TeV	JHEP 01 (2017) 076	CMS-EXO-16-021 1610.02960
39	CMS Collaboration	Search for a Higgs boson decaying into a Z and a photon in pp collisions at $\sqrt{s} =$ 7 and 8 TeV	PLB 726 (2013) 587	CMS-HIG-13-006 1307.5515
40	ATLAS Collaboration	Search for Higgs boson decays to a photon and a Z boson in pp collisions at $\sqrt{s}=$ 7 and 8 TeV with the ATLAS detector	PLB 732 (2014) 8	1402.3051
41	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
42	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
43	CMS Collaboration	Performance of CMS muon reconstruction in pp collision events at $\sqrt{s} =$ 7 TeV	JINST 7 (2012) P10002	CMS-MUO-10-004 1206.4071
44	CMS Collaboration	The CMS trigger system	JINST 12 (2017) P01020	CMS-TRG-12-001 1609.02366
45	CMS Collaboration	The CMS experiment at the CERN LHC	JINST 3 (2008) S08004	CMS-00-001
46	T. Sjostrand, S. Mrenna, and P. Z. Skands	A brief introduction to PYTHIA 8.1	CPC 178 (2008) 852	0710.3820
47	P. Skands, S. Carrazza, and J. Rojo	Tuning PYTHIA 8.1: the Monash 2013 tune	EPJC 74 (2014) 3024	1404.5630
48	CMS Collaboration	Event generator tunes obtained from underlying event and multiparton scattering measurements	EPJC 76 (2016) 155	CMS-GEN-14-001 1512.00815
49	J. Alwall et al.	MadGraph 5: going beyond	JHEP 06 (2011) 128	1106.0522
50	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
51	NNPDF Collaboration	Parton distributions for the LHC Run II	JHEP 04 (2015) 040	1410.8849
52	GEANT4 Collaboration	GEANT4 --- a simulation toolkit	NIMA 506 (2003) 250
53	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
54	M. Cacciari, G. P. Salam, and G. Soyez	The anti- $k_\text{t}$ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
55	M. Cacciari, G. P. Salam, and G. Soyez	FastJet user manual	EPJC 72 (2012) 1896	1111.6097
56	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
57	M. Cacciari and G. P. Salam	Pileup subtraction using jet areas	PLB 659 (2008) 119	0707.1378
58	H.-J. Yang, B. P. Roe, and J. Zhu	Studies of boosted decision trees for MiniBooNE particle identification	NIMA 555 (2005) 370	physics/0508045
59	H. Voss, A. Hocker, J. Stelzer, and F. Tegenfeldt	TMVA, the toolkit for multivariate data analysis with ROOT	in XIth International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT), p. 40 2007 [PoS(ACAT)040]	physics/0703039
60	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
61	CMS Collaboration	Determination of jet energy calibration and transverse momentum resolution in CMS	JINST 6 (2011) P11002	CMS-JME-10-011 1107.4277
62	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
63	S. D. Ellis, C. K. Vermilion, and J. R. Walsh	Techniques for improved heavy particle searches with jet substructure	PRD 80 (2009) 051501	0903.5081
64	S. D. Ellis, C. K. Vermilion, and J. R. Walsh	Recombination algorithms and jet substructure: pruning as a tool for heavy particle searches	PRD 81 (2010) 094023	0912.0033
65	Y. L. Dokshitzer, G. D. Leder, S. Moretti, and B. R. Webber	Better jet clustering algorithms	JHEP 08 (1997) 001	hep-ph/9707323
66	CMS Collaboration	Identification techniques for highly boosted W bosons that decay into hadrons	JHEP 12 (2014) 017	CMS-JME-13-006 1410.4227
67	J. Thaler and K. Van Tilburg	Identifying boosted objects with $N$ -subjettiness	JHEP 03 (2011) 015	1011.2268
68	J. Thaler and K. Van Tilburg	Maximizing boosted top identification by minimizing $N$ -subjettiness	JHEP 02 (2012) 093	1108.2701
69	CMS Collaboration	Jet algorithms performance in 13 TeV data	CMS-PAS-JME-16-003	CMS-PAS-JME-16-003
70	CMS Collaboration	Identification of b-quark jets with the CMS experiment	JINST 8 (2013) P04013	CMS-BTV-12-001 1211.4462
71	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
72	ATLAS Collaboration	Search for strong gravity in multijet final states produced in pp collisions at $\sqrt{s} =$ 13 TeV using the ATLAS detector at the LHC	JHEP 03 (2016) 026	1512.02586
73	CDF Collaboration	Search for new particles decaying into dijets in proton-antiproton collisions at $\sqrt{s} =$ 1.96 TeV	PRD 79 (2009) 112002	0812.4036
74	UA2 Collaboration	A measurement of two-jet decays of the $W$ and $Z$ bosons at the CERN ${\bar{p} p}$ collider	Z. Phys. C 49 (1991) 17
75	R. A. Fisher	On the interpretation of $\chi^2$ from contingency tables, and the calculation of $p$	J. Roy. Stat. Soc. 85 (1922) 87
76	CMS Collaboration	Search for Resonant Production of High-Mass Photon Pairs in Proton-Proton Collisions at $\sqrt s =$ 8 and 13 TeV	PRL 117 (2016) 051802	CMS-EXO-16-018 1606.04093
77	F. Garwood	Fiducial limits for the Poisson distribution	Biometrika 28 (1936) 437
78	M. J. Oreglia	A study of the reactions $\psi' \to \gamma\gamma \psi$	PhD thesis, Stanford University, 1980 SLAC Report SLAC-R-236, see A
79	A. L. Read	Linear interpolation of histograms	NIMA 425 (1999) 357
80	CMS Collaboration	CMS luminosity measurements for the 2016 data-taking period	CMS-PAS-LUM-17-001	CMS-PAS-LUM-17-001
81	J. Butterworth et al.	PDF4LHC recommendations for LHC Run II	JPG 43 (2016) 023001	1510.03865
82	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
83	G. Cowan, K. Cranmer, E. Gross, and O. Vitells	Asymptotic formulae for likelihood-based tests of new physics	EPJC 71 (2011) 1554	1007.1727
84	T. Junk	Confidence level computation for combining searches with small statistics	NIMA 434 (1999) 435	hep-ex/9902006
85	A. L. Read	Presentation of search results: the $CL_s$ technique	in Durham IPPP Workshop: Advanced Statistical Techniques in Particle Physics, p. 2693 Durham, UK, March, 2002 [JPG 28 (2002) 2693]
86	ATLAS and CMS Collaborations	Procedure for the LHC Higgs boson search combination in Summer 2011	ATL-PHYS-PUB-2011-011, CMS NOTE-2011/005
87	Particle Data Group Collaboration	Review of Particle Physics	CPC 40 (2016) 100001