CMS-PAS-SMP-22-018 | ||
Measurement of $ \mathrm{WZ}\gamma $ production and constraints on new physics scenarios in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | ||
CMS Collaboration | ||
23 July 2024 | ||
Abstract: A measurement of the $ \mathrm{WZ}\gamma $ triboson production predicted by the standard model is reported. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of $ \sqrt{s}= $ 13 TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. The analysis uses the final state containing three charged leptons, $ \mathrm{WZ}\rightarrow\ell\nu\ell'\ell' $, where $ \ell, \ell' = \mathrm{e} $ or $ \mu $, plus an additional photon. The observed (expected) significance of the $ \mathrm{WZ}\gamma $ signal is 5.4 (3.8) standard deviations. The cross section is measured in a fiducial region to be 5.48 $ \pm $ 1.11 fb, which can be compared with the prediction of 3.69 $ \pm $ 0.15 $ \ (\mathrm{PDF}) \pm 0.19\ (\mathrm{scale}) $ fb at next-to-leading order in quantum chromodynamics. Exclusions limits at the 95% confidence level are placed on anomalous quartic gauge couplings and on the production of massive axion-like particles. | ||
Links: CDS record (PDF) ; CADI line (restricted) ; |
Figures | |
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Figure 1:
Representative Feynman diagrams for $ \mathrm{W}\mathrm{Z}\gamma $ production at LO in QCD, including production through QGCs (left), TGCs (second from left) and multiperipheral (third from left). The right plot shows the $ \mathrm{W}\mathrm{Z}\gamma $ production including an ALP which decays to a Z boson and a photon. |
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Figure 1-a:
Representative Feynman diagrams for $ \mathrm{W}\mathrm{Z}\gamma $ production at LO in QCD, including production through QGCs (left), TGCs (second from left) and multiperipheral (third from left). The right plot shows the $ \mathrm{W}\mathrm{Z}\gamma $ production including an ALP which decays to a Z boson and a photon. |
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Figure 1-b:
Representative Feynman diagrams for $ \mathrm{W}\mathrm{Z}\gamma $ production at LO in QCD, including production through QGCs (left), TGCs (second from left) and multiperipheral (third from left). The right plot shows the $ \mathrm{W}\mathrm{Z}\gamma $ production including an ALP which decays to a Z boson and a photon. |
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Figure 1-c:
Representative Feynman diagrams for $ \mathrm{W}\mathrm{Z}\gamma $ production at LO in QCD, including production through QGCs (left), TGCs (second from left) and multiperipheral (third from left). The right plot shows the $ \mathrm{W}\mathrm{Z}\gamma $ production including an ALP which decays to a Z boson and a photon. |
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Figure 1-d:
Representative Feynman diagrams for $ \mathrm{W}\mathrm{Z}\gamma $ production at LO in QCD, including production through QGCs (left), TGCs (second from left) and multiperipheral (third from left). The right plot shows the $ \mathrm{W}\mathrm{Z}\gamma $ production including an ALP which decays to a Z boson and a photon. |
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Figure 2:
The distributions of the kinematic variables used in the simultaneous fit for the nonprompt $ \ell $ CR (left top), nonprompt $ \gamma $ CR (right top), ZZ CR (left bottom), and SR (right bottom) after the fit to the data. The black points with error bars represent the data and their statistical uncertainties, whereas the shaded band represents the predicted uncertainties. The bottom panel in each figure shows the ratio of the number of events observed in data to that of the total SM prediction. The shaded bands represent the uncertainties in the predicted yields. The vertical bars on the filled circles represent the statistical uncertainties in the data. |
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Figure 2-a:
The distributions of the kinematic variables used in the simultaneous fit for the nonprompt $ \ell $ CR (left top), nonprompt $ \gamma $ CR (right top), ZZ CR (left bottom), and SR (right bottom) after the fit to the data. The black points with error bars represent the data and their statistical uncertainties, whereas the shaded band represents the predicted uncertainties. The bottom panel in each figure shows the ratio of the number of events observed in data to that of the total SM prediction. The shaded bands represent the uncertainties in the predicted yields. The vertical bars on the filled circles represent the statistical uncertainties in the data. |
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Figure 2-b:
The distributions of the kinematic variables used in the simultaneous fit for the nonprompt $ \ell $ CR (left top), nonprompt $ \gamma $ CR (right top), ZZ CR (left bottom), and SR (right bottom) after the fit to the data. The black points with error bars represent the data and their statistical uncertainties, whereas the shaded band represents the predicted uncertainties. The bottom panel in each figure shows the ratio of the number of events observed in data to that of the total SM prediction. The shaded bands represent the uncertainties in the predicted yields. The vertical bars on the filled circles represent the statistical uncertainties in the data. |
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Figure 2-c:
The distributions of the kinematic variables used in the simultaneous fit for the nonprompt $ \ell $ CR (left top), nonprompt $ \gamma $ CR (right top), ZZ CR (left bottom), and SR (right bottom) after the fit to the data. The black points with error bars represent the data and their statistical uncertainties, whereas the shaded band represents the predicted uncertainties. The bottom panel in each figure shows the ratio of the number of events observed in data to that of the total SM prediction. The shaded bands represent the uncertainties in the predicted yields. The vertical bars on the filled circles represent the statistical uncertainties in the data. |
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Figure 2-d:
The distributions of the kinematic variables used in the simultaneous fit for the nonprompt $ \ell $ CR (left top), nonprompt $ \gamma $ CR (right top), ZZ CR (left bottom), and SR (right bottom) after the fit to the data. The black points with error bars represent the data and their statistical uncertainties, whereas the shaded band represents the predicted uncertainties. The bottom panel in each figure shows the ratio of the number of events observed in data to that of the total SM prediction. The shaded bands represent the uncertainties in the predicted yields. The vertical bars on the filled circles represent the statistical uncertainties in the data. |
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Figure 3:
(left) Expected and observed 95% upper limits on the product of the cross section and branching fraction $ \sigma(pp\rightarrow Wa)\mathcal{B}(W\rightarrow \ell^+ \nu_\ell)\mathcal{B}(a\rightarrow \mathrm{Z}\gamma)\mathcal{B}(\mathrm{Z}\rightarrow \ell^+ \ell^-) $ as a function of the ALP mass. The red line corresponds to the theoretical prediction for 1$ /f_a= $ 2 TeV$^{-1} $. (right) Expected and observed 95% upper limits on the photophobic ALP model parameter 1$ /f_a $ as a function of ALP mass reinterpreted from 1$ /f_a= $ 2 TeV$^{-1} $. The blue line indicates the point at which the energy scale of $ f_a $ matches that of the ALP mass. |
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Figure 3-a:
(left) Expected and observed 95% upper limits on the product of the cross section and branching fraction $ \sigma(pp\rightarrow Wa)\mathcal{B}(W\rightarrow \ell^+ \nu_\ell)\mathcal{B}(a\rightarrow \mathrm{Z}\gamma)\mathcal{B}(\mathrm{Z}\rightarrow \ell^+ \ell^-) $ as a function of the ALP mass. The red line corresponds to the theoretical prediction for 1$ /f_a= $ 2 TeV$^{-1} $. (right) Expected and observed 95% upper limits on the photophobic ALP model parameter 1$ /f_a $ as a function of ALP mass reinterpreted from 1$ /f_a= $ 2 TeV$^{-1} $. The blue line indicates the point at which the energy scale of $ f_a $ matches that of the ALP mass. |
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Figure 3-b:
(left) Expected and observed 95% upper limits on the product of the cross section and branching fraction $ \sigma(pp\rightarrow Wa)\mathcal{B}(W\rightarrow \ell^+ \nu_\ell)\mathcal{B}(a\rightarrow \mathrm{Z}\gamma)\mathcal{B}(\mathrm{Z}\rightarrow \ell^+ \ell^-) $ as a function of the ALP mass. The red line corresponds to the theoretical prediction for 1$ /f_a= $ 2 TeV$^{-1} $. (right) Expected and observed 95% upper limits on the photophobic ALP model parameter 1$ /f_a $ as a function of ALP mass reinterpreted from 1$ /f_a= $ 2 TeV$^{-1} $. The blue line indicates the point at which the energy scale of $ f_a $ matches that of the ALP mass. |
Tables | |
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Table 1:
Summary of the event selections in SR, nonprompt CRs, and the ZZ CR. The nonprompt CRs are used to validate and constrain the nonprompt lepton and photon contributions, and the ZZ CR is used to constrain the ZZ contribution. A ``$ \text{---} $'' indicates that no requirement is placed on the corresponding observable. The aQGC SR is similar to the SR with the exception that $ p_{\mathrm{T}}^{\gamma} > $ 60 GeV. |
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Table 2:
Expected yields after the combined fit for the relevant processes in the signal region and control regions. All analysis uncertainties are included. |
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Table 3:
Summary of the relative contributions of typical uncertainties to the value of the signal strength in the measurement of the SM $ \mathrm{W}\mathrm{Z}\gamma $ signal. |
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Table 4:
Exclusion limits at the 95% CL for each aQGC coefficient, assuming all other coefficients are set to zero. Unitarity bounds corresponding to each operator are also listed. |
Summary |
A measurement of the standard model (SM) production of $ \mathrm{W}\mathrm{Z}\gamma $ with both W and Z boson decay leptonically has been presented. Results are based on the data collected in proton-proton collisions at $ \sqrt{s}= $ 13 TeV in the CMS detector during 2016-2018, which corresponding to a integrated luminosity of 138 fb$ ^{-1} $. Events are selected by requiring an identified photon, missing transverse momentum, as well as three identified leptons, of which two correspond to an on-shell Z boson. The observed significance for the SM signal is 5.4 standard deviations, while a significance of 3.8 standard deviations is expected based on the SM prediction. The measured fiducial cross section of leptonic WZ$ \gamma $ production is $ \sigma_{\mathrm{p}\mathrm{p}\rightarrow\ell\nu\ell'\ell'\gamma}= $ 5.48 $ \pm $ 1.11 fb, where $ \ell = \mathrm{e} $ or $ \mu $, is in good agreement with the NLO QCD prediction. Constraints are placed on anomalous quartic gauge couplings in terms of dimension-eight operators in effective field theory. Upper limits on the photophobic axion-like particles (ALPs) are set as a function of ALPs mass. Equivalent limits for the ALPs mass and coupling parameters within the ALPs model are reported, including some of the most stringent constraints for mass points between $ m_a= $ 200 GeV and $ m_a= $ 400 GeV, as well as the first interpretation for masses between $ m_a= $ 110 GeV and $ m_a= $ 200 GeV. |
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 | ATLAS Collaboration | Observation of $ WZ\gamma $ production in $ pp $ collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector | PRL 132 (2024) 021802 | 2305.16994 |
5 | C. Degrande et al. | Effective field theory: A modern approach to anomalous couplings | Annals Phys. 335 (2013) 21 | 1205.4231 |
6 | S. Weinberg | A New Light Boson? | PRL 40 (1978) 223 | |
7 | F. Wilczek | Problem of Strong $ P $ and $ T $ Invariance in the Presence of Instantons | PRL 40 (1978) 279 | |
8 | K. Choi, S. H. Im, and C. Sub Shin | Recent Progress in the Physics of Axions and Axion-Like Particles | Ann. Rev. Nucl. Part. Sci. 71 (2021) 225 | 2012.05029 |
9 | ATLAS Collaboration | Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb$ ^{-1} $ of Pb+Pb data with the ATLAS detector | JHEP 03 (2021) 243 | 2008.05355 |
10 | M. Bauer, M. Heiles, M. Neubert, and A. Thamm | Axion-Like Particles at Future Colliders | EPJC 79 (2019) 74 | 1808.10323 |
11 | L. Di Luzio, M. Giannotti, E. Nardi, and L. Visinelli | The landscape of QCD axion models | Phys. Rept. 870 (2020) 1 | 2003.01100 |
12 | R. D. Peccei and H. R. Quinn | CP conservation in the presence of pseudoparticles | PRL 38 (1977) 1440 | |
13 | R. D. Peccei and H. R. Quinn | Constraints imposed by CP conservation in the presence of pseudoparticles | PRD 16 (1977) 1791 | |
14 | N. Craig, A. Hook, and S. Kasko | The Photophobic ALP | JHEP 09 (2018) 028 | 1805.06538 |
15 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | |
16 | CMS Collaboration | The CMS trigger system | JINST 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
17 | 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 |
18 | R. Frederix and S. Frixione | Merging meets matching in MC@NLO | JHEP 12 (2012) 061 | 1209.6215 |
19 | E. Re | Single-top Wt-channel production matched with parton showers using the POWHEG method | EPJC 71 (2011) 1547 | 1009.2450 |
20 | P. Nason | A new method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 11 (2004) 040 | hep-ph/0409146 |
21 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with parton shower simulations: the POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
22 | 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 |
23 | 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 |
24 | J. M. Campbell and R. K. Ellis | MCFM for the Tevatron and the LHC | Nucl. Phys. Proc. Suppl. 205 (2010) 10 | 1007.3492 |
25 | O. Mattelaer | On the maximal use of Monte Carlo samples: re-weighting events at NLO accuracy | EPJC 76 (2016) 674 | 1607.00763 |
26 | 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 |
27 | NNPDF Collaboration | Parton distributions from high-precision collider data | EPJC 77 (2017) 663 | 1706.00428 |
28 | GEANT4 Collaboration | GEANT 4---a simulation toolkit | NIM A 506 (2003) 250 | |
29 | J. Allison et al. | GEANT4 developments and applications | IEEE Trans. Nucl. Sci. 53 (2006) 270 | |
30 | CMS Collaboration | Measurement of the inclusive W and Z production cross sections in pp collisions at $ \sqrt{s} = $ 7 TeV with the CMS experiment | JHEP 10 (2011) 132 | CMS-EWK-10-005 1107.4789 |
31 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
32 | 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 |
33 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-$ k_{\mathrm{T}} $ jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
34 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet user manual | EPJC 72 (2012) 1896 | 1111.6097 |
35 | CMS Collaboration | Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC | JINST 16 (2021) P05014 | CMS-EGM-17-001 2012.06888 |
36 | M. Cacciari and G. P. Salam | Pileup subtraction using jet areas | PLB 659 (2008) 119 | 0707.1378 |
37 | 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 |
38 | CMS Collaboration | Pileup mitigation at CMS in 13 TeV data | JINST 15 (2020) P09018 | CMS-JME-18-001 2003.00503 |
39 | 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 |
40 | 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 |
41 | CMS Collaboration | Performance of the CMS Level-1 trigger in proton-proton collisions at $ \sqrt{s} = $ 13 TeV | JINST 15 (2020) P10017 | CMS-TRG-17-001 2006.10165 |
42 | CMS Collaboration | Measurement of the electroweak production of Z$ \gamma $ and two jets in proton-proton collisions at $ \sqrt{s} = $ 13 TeV and constraints on anomalous quartic gauge couplings | PRD 104 (2021) 072001 | CMS-SMP-20-016 2106.11082 |
43 | CMS Collaboration | Measurement of the W$ \gamma $ Production Cross Section in Proton-Proton Collisions at $ \sqrt {s} = $ 13 TeV and Constraints on Effective Field Theory Coefficients | PRL 126 (2021) 252002 | CMS-SMP-19-002 2102.02283 |
44 | CMS Collaboration | Precision luminosity measurement in proton-proton collisions at $ \sqrt{s} = $ 13 TeV in 2015 and 2016 at CMS | EPJC 81 (2021) 800 | CMS-LUM-17-003 2104.01927 |
45 | CMS Collaboration | CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s} = $ 13 TeV | CMS Physics Analysis Summary, 2018 link |
CMS-PAS-LUM-17-004 |
46 | CMS Collaboration | CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s} = $ 13 TeV | CMS Physics Analysis Summary, 2019 link |
CMS-PAS-LUM-18-002 |
47 | J. Butterworth et al. | PDF4LHC recommendations for LHC Run II | JPG 43 (2016) 023001 | 1510.03865 |
48 | CMS Collaboration | The CMS statistical analysis and combination tool: Combine | Accepted by Comput. Softw. Big Sci, 2024 | CMS-CAT-23-001 2404.06614 |
49 | O. J. P. Eboli, M. C. Gonzalez-Garcia, and J. K. Mizukoshi | $ \mathrm{p}\mathrm{p} \rightarrow $ jje$ ^\pm \mu^\pm \nu\nu $ and jje$ ^\pm\mu^\mp\nu\nu $ at O($ \alpha^6_{\rm em} $) and O($ \alpha_{\rm em}^4 \alpha_{\rm s}^2 $) for the study of the quartic electroweak gauge boson vertex at CERN LHC | PRD 74 (2006) 073005 | hep-ph/0606118 |
50 | CMS Collaboration | Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV | EPJC 75 (2015) 212 | CMS-HIG-14-009 1412.8662 |
51 | K. Arnold et al. | VBFNLO: A parton level Monte Carlo for processes with electroweak bosons | Comput. Phys. Commun. 180 (2009) 1661 | 0811.4559 |
52 | T. Junk | Confidence level computation for combining searches with small statistics | NIM A 434 (1999) 435 | hep-ex/9902006 |
53 | A. L. Read | Presentation of search results: The CL$ _{\mathrm{s}} $ technique | JPG 28 (2002) 2693 |
Compact Muon Solenoid LHC, CERN |