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| CMS-PAS-TOP-22-008 | ||
| Evidence for tWZ production in proton-proton collisions at $ \sqrt{s} = $ 13 TeV in multilepton final states | ||
| CMS Collaboration | ||
| 24 May 2023 | ||
| Abstract: We present the first evidence for the standard model production of a top quark in association with a W and a Z boson in multilepton final states. The Z boson is reconstructed via its decays to electron or muon pairs. The analysed data were recorded by the CMS experiment at the CERN LHC from 2016 to 2018 in proton-proton collisions at $ \sqrt{s} = $ 13 TeV, and correspond to an integrated luminosity of 138 fb$ ^{-1} $. The measured cross section amounts to 0.37 $ \pm $ 0.05 (stat) $\pm$ 0.10 (syst) pb, and corresponds to an observed (expected) significance of 3.5 (1.4) standard deviations. | ||
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Links:
CDS record (PDF) ;
Physics Briefing ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, Submitted to PLB. The superseded preliminary plots can be found here. |
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| Figures | |
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Figure 1:
Representative Feynman diagram for the tWZ production at NLO accuracy in QCD. |
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Figure 2:
Output node score of tWZ in SRb (left). Output node score of tWZ in SRa for events with exactly one b jet (middle), and of $ \mathrm{t} \overline{\mathrm{t}} $ Z in SRa for events with more than one b jet (right). The WZ+light jets process is denoted with WZ+j in the legend. The grey uncertainty band shows the uncertainty after the fit. |
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Figure 2-a:
Output node score of tWZ in SRb (left). Output node score of tWZ in SRa for events with exactly one b jet (middle), and of $ \mathrm{t} \overline{\mathrm{t}} $ Z in SRa for events with more than one b jet (right). The WZ+light jets process is denoted with WZ+j in the legend. The grey uncertainty band shows the uncertainty after the fit. |
png pdf |
Figure 2-b:
Output node score of tWZ in SRb (left). Output node score of tWZ in SRa for events with exactly one b jet (middle), and of $ \mathrm{t} \overline{\mathrm{t}} $ Z in SRa for events with more than one b jet (right). The WZ+light jets process is denoted with WZ+j in the legend. The grey uncertainty band shows the uncertainty after the fit. |
png pdf |
Figure 2-c:
Output node score of tWZ in SRb (left). Output node score of tWZ in SRa for events with exactly one b jet (middle), and of $ \mathrm{t} \overline{\mathrm{t}} $ Z in SRa for events with more than one b jet (right). The WZ+light jets process is denoted with WZ+j in the legend. The grey uncertainty band shows the uncertainty after the fit. |
| Summary |
| In summary, we report the first evidence for the tWZ process in final states with three or four leptons, using the data collected by the CMS experiment at the CERN LHC from 2016 to 2018, at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. Despite the overwhelming contributions of irreducible backgrounds, we extract the signal with an observed statistical significance of 3.5 standard deviations, providing compelling evidence for the process. This study establishes the groundwork for future measurements with relevant implications for further investigation as more data is collected. |
| References | ||||
| 1 | F. Maltoni, L. Mantani, and K. Mimasu | Top-quark electroweak interactions at high energy | JHEP 10 (2019) 004 | 1904.05637 |
| 2 | H. E. Faham, F. Maltoni, K. Mimasu, and M. Zaro | Single top production in association with a WZ pair at the LHC in the SMEFT | JHEP 01 (2022) 100 | 2111.03080 |
| 3 | 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 |
| 4 | R. Frederix and S. Frixione | Merging meets matching in MC@NLO | JHEP 12 (2012) 061 | 1209.6215 |
| 5 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | |
| 6 | 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 |
| 7 | CMS Collaboration | The CMS trigger system | JINST 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
| 8 | 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 |
| 9 | 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 |
| 10 | 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 |
| 11 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
| 12 | 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 |
| 13 | 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 |
| 14 | 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 |
| 15 | T. Sjöstrand, S. Mrenna, and P. Z. Skands | A Brief Introduction to PYTHIA 8.1 | Comput. Phys. Commun. 178 (2008) 852 | 0710.3820 |
| 16 | NNPDF Collaboration | Parton distributions from high-precision collider data | no.~10, 663, 2017 EPJC 77 (2017) |
1706.00428 |
| 17 | S. Frixione et al. | Automated simulations beyond the Standard Model: supersymmetry | JHEP 12 (2019) 008 | 1907.04898 |
| 18 | F. Demartin et al. | tWH associated production at the LHC | EPJC 77 (2017) 34 | 1607.05862 |
| 19 | J. M. Campbell and R. K. Ellis | MCFM for the Tevatron and the LHC | NPB (Proc. Suppl.) 205 (2010) 10 | 1007.3492 |
| 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 | H. B. Hartanto, B. Jäger, L. Reina and D. Wackeroth | Higgs boson production in association with top quarks in the POWHEG BOX | PRD 91 (2015) 094003 | 1501.04498 |
| 24 | T. Sjöstrand et al. | An introduction to PYTHIA 8.2 | Comput. Phys. Commun. 191 (2015) 159 | 1410.3012 |
| 25 | CMS Collaboration | Extraction and validation of a new set of CMS PYTHIA 8 tunes from underlying-event measurements | EPJC 80 (2020) | CMS-GEN-17-001 1903.12179 |
| 26 | 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 |
| 27 | GEANT4 Collaboration | GEANT 4---a simulation toolkit | NIM A 506 (2003) 250 | |
| 28 | CMS Collaboration | Observation of four top quark production in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | CMS Physics Analysis Summary, 2023 CMS-PAS-TOP-22-013 |
CMS-PAS-TOP-22-013 |
| 29 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-$ k_t $ jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
| 30 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet User Manual | EPJC 72 (2012) 1896 | 1111.6097 |
| 31 | 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 |
| 32 | E. Bols et al. | Jet flavour classification using DeepJet | JINST 15 (2020) P12012 | 2008.10519 |
| 33 | CMS Collaboration | Performance of the DeepJet b tagging algorithm using 41.9 fb$ ^{-1} $ of data from proton-proton collisions at 13 TeV with Phase 1 CMS detector | CMS Detector Performance Note CMS-DP-2018-058, 2018 CDS |
|
| 34 | A. J. Larkoski, S. Marzani, G. Soyez, and J. Thaler | Soft Drop | JHEP 05 (2014) 146 | 1402.2657 |
| 35 | Particle Data Group Collaboration | Review of Particle Physics | PRD 98 (2018) 030001 | |
| 36 | CMS Collaboration | Measurement of the $ t $-channel single top quark production cross section in pp collisions at $ \sqrt{s} = $ 7 TeV | PRL 107 (2011) 091802 | CMS-TOP-10-008 1106.3052 |
| 37 | M. Abadi et al. | Tensorflow: large-scale machine learning on heterogeneous systems | Software (2015) available from tensorflow.org |
|
| 38 | CMS Collaboration | Measurement of top quark pair production in association with a Z boson in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JHEP 03 (2020) 056 | CMS-TOP-18-009 1907.11270 |
| 39 | CMS Collaboration | Inclusive and differential cross section measurements of single top quark production in association with a Z boson in proton-proton collisions at $ \sqrt{s} $ = 13 TeV | JHEP 02 (2022) 107 | CMS-TOP-20-010 2111.02860 |
| 40 | 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 |
| 41 | R. J. Barlow and C. Beeston | Fitting using finite Monte Carlo samples | Comput. Phys. Commun. 77 (1993) 219 | |
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