CMSPASEXO22013  
Search for $ t $channel scalar and vector leptoquark exchange in the high mass dimuon and dielectron spectrum in protonproton collisions at $ \sqrt{s} = $ 13 TeV  
CMS Collaboration  
25 July 2024  
Abstract: A search for $ t $channel exchange of leptoquarks (LQs) is performed using protonproton collision data collected at $ \sqrt{s}= $ 13 TeV with the CMS detector at the CERN LHC. The data correspond to an integrated luminosity of 138 fb$ ^{1} $. The search spans scenarios with scalar and vector LQs that couple up and down quarks to electrons and muons. Dielectron and dimuon final states are considered, with dilepton invariant masses above 500 GeV. The differential distributions of dilepton events are fit to templates built from reweighted samples of simulated standard model events. This method is able to probe higher LQ masses than previous pairproduction and singleproduction searches. Limits are set on LQfermion coupling strengths for LQ masses up to 5 TeV. Based on the results, scalar LQs are excluded for masses up to 5 TeV for a coupling strength of 1.2, and vector LQs are excluded for masses up to 5 TeV for a coupling strength of 1.5.  
Links: CDS record (PDF) ; CADI line (restricted) ; 
Figures  
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Figure 1:
Leading order diagrams for SM DY production (left) and $ t $channel LQ exchange (right). The LQ amplitude interferes with the $ \mathrm{Z}/\gamma^{*} $ amplitude. 
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Figure 2:
A comparison of data and expected background distributions in dilepton invariant mass (upper row), $ c_\mathrm{R} $ (middle row) and dilepton rapidity (lower row). The left (right) plots show the $ \mu\mu $ ($ \mathrm{e}\mathrm{e} $) channel. The blue histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{S}_{\mu\mathrm{u}} $) with $ y_{\mathrm{e}\mathrm{u}}(y_{\mu\mathrm{u}})= $ 2.0, while the yellow histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{V}_{\mu\mathrm{u}} $) with $ g_{\mathrm{e}\mathrm{u}}(g_{\mu\mathrm{u}})= $ 1.0. The black points with error bars represent the data and their statistical uncertainties. The background expectation is shown as stacked histograms. The hatched band shows the total systematic uncertainty in the expected background yield. The lower panels show the ratio of the data to the expectation. The gray bands represents the normalized uncertainty in the predicted yield. The error bars in the ratio plot represent the normalized statistical uncertainty of the data. 
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Figure 2a:
A comparison of data and expected background distributions in dilepton invariant mass (upper row), $ c_\mathrm{R} $ (middle row) and dilepton rapidity (lower row). The left (right) plots show the $ \mu\mu $ ($ \mathrm{e}\mathrm{e} $) channel. The blue histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{S}_{\mu\mathrm{u}} $) with $ y_{\mathrm{e}\mathrm{u}}(y_{\mu\mathrm{u}})= $ 2.0, while the yellow histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{V}_{\mu\mathrm{u}} $) with $ g_{\mathrm{e}\mathrm{u}}(g_{\mu\mathrm{u}})= $ 1.0. The black points with error bars represent the data and their statistical uncertainties. The background expectation is shown as stacked histograms. The hatched band shows the total systematic uncertainty in the expected background yield. The lower panels show the ratio of the data to the expectation. The gray bands represents the normalized uncertainty in the predicted yield. The error bars in the ratio plot represent the normalized statistical uncertainty of the data. 
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Figure 2b:
A comparison of data and expected background distributions in dilepton invariant mass (upper row), $ c_\mathrm{R} $ (middle row) and dilepton rapidity (lower row). The left (right) plots show the $ \mu\mu $ ($ \mathrm{e}\mathrm{e} $) channel. The blue histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{S}_{\mu\mathrm{u}} $) with $ y_{\mathrm{e}\mathrm{u}}(y_{\mu\mathrm{u}})= $ 2.0, while the yellow histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{V}_{\mu\mathrm{u}} $) with $ g_{\mathrm{e}\mathrm{u}}(g_{\mu\mathrm{u}})= $ 1.0. The black points with error bars represent the data and their statistical uncertainties. The background expectation is shown as stacked histograms. The hatched band shows the total systematic uncertainty in the expected background yield. The lower panels show the ratio of the data to the expectation. The gray bands represents the normalized uncertainty in the predicted yield. The error bars in the ratio plot represent the normalized statistical uncertainty of the data. 
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Figure 2c:
A comparison of data and expected background distributions in dilepton invariant mass (upper row), $ c_\mathrm{R} $ (middle row) and dilepton rapidity (lower row). The left (right) plots show the $ \mu\mu $ ($ \mathrm{e}\mathrm{e} $) channel. The blue histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{S}_{\mu\mathrm{u}} $) with $ y_{\mathrm{e}\mathrm{u}}(y_{\mu\mathrm{u}})= $ 2.0, while the yellow histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{V}_{\mu\mathrm{u}} $) with $ g_{\mathrm{e}\mathrm{u}}(g_{\mu\mathrm{u}})= $ 1.0. The black points with error bars represent the data and their statistical uncertainties. The background expectation is shown as stacked histograms. The hatched band shows the total systematic uncertainty in the expected background yield. The lower panels show the ratio of the data to the expectation. The gray bands represents the normalized uncertainty in the predicted yield. The error bars in the ratio plot represent the normalized statistical uncertainty of the data. 
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Figure 2d:
A comparison of data and expected background distributions in dilepton invariant mass (upper row), $ c_\mathrm{R} $ (middle row) and dilepton rapidity (lower row). The left (right) plots show the $ \mu\mu $ ($ \mathrm{e}\mathrm{e} $) channel. The blue histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{S}_{\mu\mathrm{u}} $) with $ y_{\mathrm{e}\mathrm{u}}(y_{\mu\mathrm{u}})= $ 2.0, while the yellow histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{V}_{\mu\mathrm{u}} $) with $ g_{\mathrm{e}\mathrm{u}}(g_{\mu\mathrm{u}})= $ 1.0. The black points with error bars represent the data and their statistical uncertainties. The background expectation is shown as stacked histograms. The hatched band shows the total systematic uncertainty in the expected background yield. The lower panels show the ratio of the data to the expectation. The gray bands represents the normalized uncertainty in the predicted yield. The error bars in the ratio plot represent the normalized statistical uncertainty of the data. 
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Figure 2e:
A comparison of data and expected background distributions in dilepton invariant mass (upper row), $ c_\mathrm{R} $ (middle row) and dilepton rapidity (lower row). The left (right) plots show the $ \mu\mu $ ($ \mathrm{e}\mathrm{e} $) channel. The blue histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{S}_{\mu\mathrm{u}} $) with $ y_{\mathrm{e}\mathrm{u}}(y_{\mu\mathrm{u}})= $ 2.0, while the yellow histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{V}_{\mu\mathrm{u}} $) with $ g_{\mathrm{e}\mathrm{u}}(g_{\mu\mathrm{u}})= $ 1.0. The black points with error bars represent the data and their statistical uncertainties. The background expectation is shown as stacked histograms. The hatched band shows the total systematic uncertainty in the expected background yield. The lower panels show the ratio of the data to the expectation. The gray bands represents the normalized uncertainty in the predicted yield. The error bars in the ratio plot represent the normalized statistical uncertainty of the data. 
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Figure 2f:
A comparison of data and expected background distributions in dilepton invariant mass (upper row), $ c_\mathrm{R} $ (middle row) and dilepton rapidity (lower row). The left (right) plots show the $ \mu\mu $ ($ \mathrm{e}\mathrm{e} $) channel. The blue histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{S}_{\mu\mathrm{u}} $) with $ y_{\mathrm{e}\mathrm{u}}(y_{\mu\mathrm{u}})= $ 2.0, while the yellow histogram represents the signal yield of a hypothetical 2.5 TeV $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ ($ \mathrm{V}_{\mu\mathrm{u}} $) with $ g_{\mathrm{e}\mathrm{u}}(g_{\mu\mathrm{u}})= $ 1.0. The black points with error bars represent the data and their statistical uncertainties. The background expectation is shown as stacked histograms. The hatched band shows the total systematic uncertainty in the expected background yield. The lower panels show the ratio of the data to the expectation. The gray bands represents the normalized uncertainty in the predicted yield. The error bars in the ratio plot represent the normalized statistical uncertainty of the data. 
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Figure 3:
The observed data in the dielectron channel and the fitted signalplusbackground templates, shown for the $ \mathrm{S}_{\mathrm{e}\mathrm{u}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 4:
The observed data in the dielectron channel and the fitted signalplusbackground templates, shown for the $ \mathrm{S}_{\mathrm{e}\mathrm{d}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 5:
The observed data in the dimuon channel and the fitted signalplusbackground templates, shown for the $ \mathrm{S}_{\mu\mathrm{u}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 6:
The observed data in the dimuon channel and the fitted signalplusbackground templates, shown for the $ \mathrm{S}_{\mu\mathrm{d}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 7:
The observed data in the dielectron channel and the fitted signalplusbackground templates, shown for the $ \mathrm{V}_{\mathrm{e}\mathrm{u}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 8:
The observed data in the dielectron channel and the fitted signalplusbackground templates, shown for the $ \mathrm{V}_{\mathrm{e}\mathrm{d}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 9:
The observed data in the dimuon channel and the fitted signalplusbackground templates, shown for the $ \mathrm{V}_{\mu\mathrm{u}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 10:
The observed data in the dimuon channel and the fitted signalplusbackground templates, shown for the $ \mathrm{V}_{\mu\mathrm{d}} $ scenario with a candidate LQ mass of 2.5 TeV. The black points are the observed data, the stacked histograms represent the backgrounds, and the yellow histogram shows the fitted LQ signal multiplied by 10. Distributions of events are binned in reconstructed $ m_{\ell\ell} $, $ y $ and $ c_\mathrm{R} $. 
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Figure 11:
Upper limits at 95% CL on the LQfermion couplings, $ y_{\mathrm{e}\mathrm{u}} $ (left) and $ y_{\mathrm{e}\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for scalar LQs coupling to electrons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 11a:
Upper limits at 95% CL on the LQfermion couplings, $ y_{\mathrm{e}\mathrm{u}} $ (left) and $ y_{\mathrm{e}\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for scalar LQs coupling to electrons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 11b:
Upper limits at 95% CL on the LQfermion couplings, $ y_{\mathrm{e}\mathrm{u}} $ (left) and $ y_{\mathrm{e}\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for scalar LQs coupling to electrons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 12:
Upper limits at 95% CL on the LQfermion couplings, $ y_{\mu\mathrm{u}} $ (left) and $ y_{\mu\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for scalar LQs coupling to muons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 12a:
Upper limits at 95% CL on the LQfermion couplings, $ y_{\mu\mathrm{u}} $ (left) and $ y_{\mu\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for scalar LQs coupling to muons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 12b:
Upper limits at 95% CL on the LQfermion couplings, $ y_{\mu\mathrm{u}} $ (left) and $ y_{\mu\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for scalar LQs coupling to muons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 13:
Upper limits at 95% CL on the LQfermion couplings, $ g_{\mathrm{e}\mathrm{u}} $ (left) and $ g_{\mathrm{e}\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for vector LQs coupling to electrons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 13a:
Upper limits at 95% CL on the LQfermion couplings, $ g_{\mathrm{e}\mathrm{u}} $ (left) and $ g_{\mathrm{e}\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for vector LQs coupling to electrons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 13b:
Upper limits at 95% CL on the LQfermion couplings, $ g_{\mathrm{e}\mathrm{u}} $ (left) and $ g_{\mathrm{e}\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for vector LQs coupling to electrons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 14:
Upper limits at 95% CL on the LQfermion couplings, $ g_{\mu\mathrm{u}} $ (left) and $ g_{\mu\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for vector LQs coupling to muons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 14a:
Upper limits at 95% CL on the LQfermion couplings, $ g_{\mu\mathrm{u}} $ (left) and $ g_{\mu\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for vector LQs coupling to muons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
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Figure 14b:
Upper limits at 95% CL on the LQfermion couplings, $ g_{\mu\mathrm{u}} $ (left) and $ g_{\mu\mathrm{d}} $ (right), versus $ m_{\rm LQ} $ for vector LQs coupling to muons. The black points show the observed limits, the red line shows the expected limits, and the yellow and blue bands show the variations on the expected limit at the 1 and 2 standard deviation levels. 
Tables  
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Table 1:
Properties of the $ R_2 $, $ \widetilde{R}_2 $, and $ U_3 $ LQs. Specifically, this analysis searches for $ R_2 $ LQs with RL couplings and charge 5/3, $ \widetilde{R}_2 $ LQs with RL couplings and charge 2/3, and $ U_3 $ LQs with charges 2/3 and 5/3. 
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Table 2:
The contribution of statistical uncertainty and individual sources of systematic uncertainty to the total variance on the fitted value of $ y_{\rm LQ}^2 $ for a scalar LQ mass of 2.5 TeV. For a given source of uncertainty, the impact is determined by fixing its associated nuisance parameter to the nominal expectation and evaluating the change in the total uncertainty. 
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Table 3:
The contribution of statistical uncertainty and individual sources of systematic uncertainty to the total variance on the fitted value of $ g_{\rm LQ}^2 $ for a vector LQ mass of 2.5 TeV. For a given source of uncertainty, the impact is determined by fixing its associated nuisance parameter to the nominal expectation and evaluating the change in the total uncertainty. 
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Table 4:
Best fit values of $ A_0 $, $ A_4 $ and $ y_{\rm LQ}^2 $ for scalar LQ models. Results are shown for a candidate $ m_{\rm LQ} $ of 2.5 TeV. 
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Table 5:
Best fit values of $ A_0 $, $ A_4 $ and $ g_{\rm LQ}^2 $ for vector LQ models. Results are shown for a candidate $ m_{\rm LQ} $ of 2.5 TeV. 
Summary 
A search for the $ t $channel exchange of leptoquarks (LQs) coupling to first and secondgeneration fermions has been presented. The search uses protonproton collision data at $ \sqrt{s} = $ 13 TeV, corresponding to an integrated luminosity of 138 fb$ ^{1} $. Both scalar and vector LQ scenarios are considered, with masses between 15 TeV for exclusive LQ couplings to an up or a down quark and an electron or a muon. The $ t $channel exchange of a LQ modifies the dilepton angular distributions at masses well below the resonance mass of the LQ. A template fit to the angular and invariant mass distributions of highmass dilepton events is used to distinguish the signal process from the dominant DrellYan background, incorporating interference effects. No evidence for such LQs is observed, and limits are set at 95% confidence level on the LQfermion couplings. Coupling values greater than 0.41.1 (0.31.0) are excluded for scalar LQs with masses from 15 TeV coupling to an electron (muon) and a firstgeneration quark. Similarly, for vector LQs, coupling values greater than 0.20.5 (0.10.4) are excluded. This search is sensitive to LQs with significantly higher masses than prior single and pairproduction searches, establishing the best limits on LQs with masses up to 5 TeV, and is also the first to set limits on vector LQs coupling to first and secondgeneration fermions. 
References  
1  J. C. Pati and A. Salam  Lepton Number as the Fourth Color  PRD 10 (1974) 275  
2  H. Georgi and S. L. Glashow  Unity of all elementary particle forces  PRL 32 (1974) 438  
3  S. Davidson and S. DescotesGenon  Minimal flavour violation for leptoquarks  JHEP 11 (2010) 073  1009.1998 
4  I. Dorsner and P. Fileviez Perez  Unification without supersymmetry: Neutrino mass, proton decay and light leptoquarks  NPB 723 (2005) 53  hepph/0504276 
5  W. Buchmuller and D. Wyler  Constraints on SU(5) type leptoquarks  PLB 177 (1986) 377  
6  B. Gripaios, M. Nardecchia, and S. A. Renner  Composite leptoquarks and anomalies in $ b $meson decays  JHEP 05 (2015) 006  1412.1791 
7  B. Gripaios  Composite leptoquarks at the LHC  JHEP 02 (2010) 045  0910.1789 
8  E. Farhi and L. Susskind  Technicolor  Phys. Rept. 74 (1981) 277  
9  S. Dimopoulos  Technicolored signatures  NPB 168 (1980) 69  
10  B. Schrempp and F. Schrempp  Light leptoquarks  PLB 153 (1985) 101  
11  M. J. Baker et al.  The coannihilation codex  JHEP 12 (2015) 120  1510.03434 
12  S.M. Choi, Y.J. Kang, H. M. Lee, and T.G. Ro  LeptoQuark portal dark matter  JHEP 10 (2018) 104  1807.06547 
13  R. Barbier et al.  Rparity violating supersymmetry  Phys. Rept. 420 (2005) 1  hepph/0406039 
14  Muon g$$2 Collaboration  Measurement of the positive muon anomalous magnetic moment to 0.46 ppm  PRL 126 (2021) 141801  2104.03281 
15  S. Borsanyi et al.  Leading hadronic contribution to the muon magnetic moment from lattice QCD  Nature 593 (2021) 51  2002.12347 
16  M. Du, J. Liang, Z. Liu, and V. Q. Tran  A vector leptoquark interpretation of the muon g$$2 and $ b $ anomalies  2104.05685  
17  I. Doršner et al.  Physics of leptoquarks in precision experiments and at particle colliders  Phys. Rept. 641 (2016) 1  1603.04993 
18  CMS Collaboration  Search for a thirdgeneration leptoquark coupled to a $\tau$ lepton and a b quark through single, pair, and nonresonant production in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JHEP 05 (2024) 311  CMSEXO19016 2308.07826 
19  CMS Collaboration  Searches for additional Higgs bosons and for vector leptoquarks in $ \tau\tau $ final states in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JHEP 07 (2023) 073  2208.02717 
20  ATLAS Collaboration  Search for pair production of thirdgeneration leptoquarks decaying into a bottom quark and a $ \tau $lepton with the ATLAS detector  EPJC 83 (2023) 1075  2303.01294 
21  ATLAS Collaboration  Search for leptoquarks decaying into the b$\tau$ final state in $ pp $ collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector  JHEP 10 (2023) 001  2305.15962 
22  ATLAS Collaboration  Search for pairs of scalar leptoquarks decaying into quarks and electrons or muons in $ \sqrt{s} = $ 13 TeV $ pp $ collisions with the ATLAS detector  JHEP 10 (2020) 112  2006.05872 
23  CMS Collaboration  Search for single production of scalar leptoquarks in protonproton collisions at $ \sqrt{s} = $ 8 TeV  PRD 93 (2016) 032005  CMSEXO12043 1509.03750 
24  CMS Collaboration  Search for pair production of firstgeneration scalar leptoquarks at $ \sqrt{s} = $ 13 TeV  PRD 99 (2019) 052002  CMSEXO17009 1811.01197 
25  CMS Collaboration  Search for pair production of secondgeneration leptoquarks at $ \sqrt{s}= $ 13 TeV  PRD 99 (2019) 032014  CMSEXO17003 1808.05082 
26  N. Raj  Anticipating nonresonant new physics in dilepton angular spectra at the LHC  PRD 95 (2017) 015011  1610.03795 
27  I. Bigaran and R. R. Volkas  Getting chirality right: Single scalar leptoquark solutions to the $ (g{}2)_{e,\mu} $ puzzle  PRD 102 (2020) 075037  2002.12544 
28  D. Bečirević, N. Košnik, O. Sumensari, and R. Zukanovich Funchal  Palatable leptoquark scenarios for lepton flavor violation in exclusive $ b\to s\ell_1\ell_2 $ modes  JHEP 11 (2016) 035  1608.07583 
29  J. C. Collins and D. E. Soper  Angular Distribution of Dileptons in HighEnergy Hadron Collisions  PRD 16 (1977) 2219  
30  CMS Collaboration  Measurement of the DrellYan forwardbackward asymmetry at high dilepton masses in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JHEP 2022 (2022) 063  CMSSMP21002 2202.12327 
31  E. Mirkes  Angular decay distribution of leptons from W bosons at NLO in hadronic collisions  NPB 387 (1992) 3  
32  E. Mirkes and J. Ohnemus  Angular distributions of DrellYan lepton pairs at the Tevatron: Order $ \alpha_{s}^{2} $ corrections and Monte Carlo studies  PRD 51 (1995) 4891  hepph/9412289 
33  CMS Collaboration  The CMS experiment at the CERN LHC  JINST 3 (2008) S08004  
34  CMS Collaboration  Development of the CMS detector for the CERN LHC Run 3  JINST 19 (2024) P05064  CMSPRF21001 2309.05466 
35  CMS Collaboration  Performance of the CMS Level1 trigger in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JINST 15 (2020) P10017  CMSTRG17001 2006.10165 
36  CMS Collaboration  The CMS trigger system  JINST 12 (2017) P01020  CMSTRG12001 1609.02366 
37  CMS Collaboration  Particleflow reconstruction and global event description with the CMS detector  JINST 12 (2017) P10003  CMSPRF14001 1706.04965 
38  CMS Collaboration  Technical proposal for the PhaseII upgrade of the Compact Muon Solenoid  CMS Technical Proposal CERNLHCC2015010, CMSTDR1502, 2015 CDS 

39  CMS Collaboration  Performance of the CMS muon detector and muon reconstruction with protonproton collisions at $ \sqrt{s}= $ 13 TeV  JINST 13 (2018) P06015  CMSMUO16001 1804.04528 
40  CMS Collaboration  Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC  JINST 16 (2021) P05014  CMSEGM17001 2012.06888 
41  M. Cacciari, G. P. Salam, and G. Soyez  The anti$ k_{\mathrm{T}} $ jet clustering algorithm  JHEP 04 (2008) 063  0802.1189 
42  M. Cacciari, G. P. Salam, and G. Soyez  FastJet user manual  EPJC 72 (2012) 1896  1111.6097 
43  CMS Collaboration  Pileup mitigation at CMS in 13 TeV data  JINST 15 (2020) P09018  CMSJME18001 2003.00503 
44  CMS Collaboration  Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV  JINST 12 (2017) P02014  CMSJME13004 1607.03663 
45  CMS Collaboration  Performance of missing transverse momentum reconstruction in protonproton collisions at $ \sqrt{s} = $ 13 TeV using the CMS detector  JINST 14 (2019) P07004  CMSJME17001 1903.06078 
46  J. Alwall et al.  The automated computation of treelevel and nexttoleading order differential cross sections, and their matching to parton shower simulations  JHEP 07 (2014) 079  1405.0301 
47  T. Sjöstrand et al.  An introduction to PYTHIA 8.2  Comput. Phys. Commun. 191 (2015) 159  1410.3012 
48  R. D. Ball et al.  A first unbiased global NLO determination of parton distributions and their uncertainties  NPB 838 (2010) 136  1002.4407 
49  NNPDF Collaboration  Parton distributions for the LHC Run II  JHEP 04 (2015) 040  1410.8849 
50  P. Nason  A new method for combining NLO QCD with shower Monte Carlo algorithms  JHEP 11 (2004) 040  hepph/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  A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX  JHEP 06 (2010) 043  1002.2581 
53  S. Frixione, P. Nason, and G. Ridolfi  A positiveweight nexttoleadingorder Monte Carlo for heavy flavour hadroproduction  JHEP 09 (2007) 126  0707.3088 
54  CMS Collaboration  Investigations of the impact of the parton shower tuning in Pythia 8 in the modelling of $ \mathrm{t\overline{t}} $ at $ \sqrt{s}= $ 8 and 13 TeV  Physics Analysis Summary, 2016 CMSPASTOP16021 
CMSPASTOP16021 
55  L. Forthomme  CepGen  A generic central exclusive processes event generator for hadronhadron collisions  Comput. Phys. Commun. 271 (2022) 108225  1808.06059 
56  J. A. M. Vermaseren  Two photon processes at very highenergies  NPB 229 (1983) 347  
57  S. Baranov, O. Düenger, H. Shooshtari, and J. Vermaseren  LPAIR: A generator for lepton pair production  in Workshop on Physics at HERA, 1991  
58  T. Sjöstrand, S. Mrenna, and P. Z. Skands  PYTHIA 6.4 physics and manual  JHEP 05 (2006) 026  hepph/0603175 
59  A. Suri and D. R. Yennie  The spacetime phenomenology of photon absorbtion and inelastic electron scattering  Annals Phys. 72 (1972) 243  
60  J. M. Campbell, R. K. Ellis, and W. T. Giele  A multithreaded version of MCFM  EPJC 75 (2015) 246  1503.06182 
61  T. Gehrmann et al.  $ W^+W^ $ production at hadron colliders in next to next to leading order QCD  PRL 113 (2014) 212001  1408.5243 
62  M. Czakon and A. Mitov  Top++: A program for the calculation of the toppair crosssection at hadron colliders  Comput. Phys. Commun. 185 (2014) 2930  1112.5675 
63  A. Crivellin and L. Schnell  Complete Lagrangian and set of Feynman rules for scalar leptoquarks  Comput. Phys. Commun. 271 (2022) 108188  2105.04844 
64  GEANT4 Collaboration  GEANT4a simulation toolkit  NIM A 506 (2003) 250  
65  CMS Collaboration  Performance of the reconstruction and identification of highmomentum muons in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JINST 15 (2020) P02027  CMSMUO17001 1912.03516 
66  Y. Afik et al.  High $ p_{\mathrm{T}} $ correlated tests of lepton universality in lepton(s) + jet(s) processes; an EFT analysis  PLB 811 (2020) 135908  2005.06457 
67  CMS Collaboration  Measurement of the differential DrellYan cross section in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JHEP 12 (2019) 059  CMSSMP17001 1812.10529 
68  CMS Collaboration  Search for physics beyond the standard model in dilepton mass spectra in protonproton collisions at $ \sqrt{s}= $ 8 TeV  JHEP 04 (2015) 025  CMSEXO12061 1412.6302 
69  Particle Data Group, P. A. Zyla et al.  Review of particle physics  Prog. Theor. Exp. Phys. 2020 (2020) 083C01  
70  CMS Collaboration  Measurement of the top quark forwardbackward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at $ \sqrt{s} = $ 13 TeV  JHEP 06 (2020) 146  CMSTOP15018 1912.09540 
71  A. Manohar, P. Nason, G. P. Salam, and G. Zanderighi  How bright is the proton? A precise determination of the photon parton distribution function  PRL 117 (2016) 242002  1607.04266 
72  A. V. Manohar, P. Nason, G. P. Salam, and G. Zanderighi  The photon content of the proton  JHEP 12 (2017) 046  1708.01256 
73  J. S. Conway  Incorporating Nuisance Parameters in Likelihoods for Multisource Spectra  in, 2011 PHYSTAT 201 (2011) 115 
1103.0354 
74  CMS Collaboration  Precision luminosity measurement in protonproton collisions at $ \sqrt{s} = $ 13 TeV in 2015 and 2016 at CMS  EPJC 81 (2021) 800  CMSLUM17003 2104.01927 
75  CMS Collaboration  CMS luminosity measurement for the 2017 datataking period at $ \sqrt{s} = $ 13 TeV  CMS Physics Analysis Summary, 2018 link 
CMSPASLUM17004 
76  CMS Collaboration  CMS luminosity measurement for the 2018 datataking period at $ \sqrt{s} = $ 13 TeV  CMS Physics Analysis Summary, 2019 link 
CMSPASLUM18002 
77  CMS Collaboration  The CMS statistical analysis and combination tool: Combine  Submitted to Comput. Softw. Big Sci, 2024  CMSCAT23001 2404.06614 
78  A. L. Read  Presentation of search results: The CL$ _{\text{s}} $ technique  JPG 28 (2002) 2693  
79  T. Junk  Confidence level computation for combining searches with small statistics  NIM A 434 (1999) 435  hepex/9902006 
80  G. Cowan, K. Cranmer, E. Gross, and O. Vitells  Asymptotic formulae for likelihoodbased tests of new physics  EPJC 71 (2011) 1554  1007.1727 
Compact Muon Solenoid LHC, CERN 