CMSEXO22018 ; CERNEP2023129  
Search for scalar leptoquarks produced via $ \tau $leptonquark scattering in pp collisions at $ \sqrt{s}= $ 13 TeV  
CMS Collaboration  
12 August 2023  
Phys. Rev. Lett. 132 (2024) 061801  
Abstract: The first search for scalar leptoquarks produced in $ \tau $leptonquark collisions is presented. It is based on a set of protonproton collision data recorded with the CMS detector at the LHC at a centerofmass energy of 13 TeV corresponding to an integrated luminosity of 138 fb$ ^{1} $. The reconstructed final state consists of a jet, significant missing transverse momentum, and a $ \tau $ lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark$ \tau $quark coupling strength.  
Links: eprint arXiv:2308.06143 [hepex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; 
Figures & Tables  Summary  Additional Figures  References  CMS Publications 

Figures  
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Figure 1:
Feynman diagram of the leptoninduced LQ production. 
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Figure 2:
Observed and expected distributions of $ m_\text{coll} $ in the $ \tau_\mathrm{h}$+jet (left), e+jet (center), and $ \mu$+jet (right) channels for the btag (upper) and nobtag (lower) subcategories with the BDT requirements selecting the most signallike events. The bands include statistical and systematic uncertainties. The background distributions are the results of the maximum likelihood fit. The signal distributions are multiplied by a factor of 5 in the e+jet and $ \mu$+jet final states to improve the readability. 
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Figure 2a:
Observed and expected distributions of $ m_\text{coll} $ in the $ \tau_\mathrm{h}$+jet channel for the btag subcategory with the BDT requirements selecting the most signallike events. The band includes statistical and systematic uncertainties. The background distributions are the results of the maximum likelihood fit. 
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Figure 2b:
Observed and expected distributions of $ m_\text{coll} $ in the e+jet channel for the btag subcategory with the BDT requirements selecting the most signallike events. The band includes statistical and systematic uncertainties. The background distributions are the results of the maximum likelihood fit. The signal distribution is multiplied by a factor of 5 to improve the readability. 
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Figure 2c:
Observed and expected distributions of $ m_\text{coll} $ in the $ \mu$+jet channel for the btag subcategory with the BDT requirements selecting the most signallike events. The band includes statistical and systematic uncertainties. The background distributions are the results of the maximum likelihood fit. The signal distribution is multiplied by a factor of 5 to improve the readability. 
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Figure 2d:
Observed and expected distributions of $ m_\text{coll} $ in the $ \tau_\mathrm{h}$+jet channel for the nobtag subcategory with the BDT requirements selecting the most signallike events. The band includes statistical and systematic uncertainties. The background distributions are the results of the maximum likelihood fit. 
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Figure 2e:
Observed and expected distributions of $ m_\text{coll} $ in the e+jet channel for the nobtag subcategory with the BDT requirements selecting the most signallike events. The band includes statistical and systematic uncertainties. The background distributions are the results of the maximum likelihood fit. The signal distribution is multiplied by a factor of 5 to improve the readability. 
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Figure 2f:
Observed and expected distributions of $ m_\text{coll} $ in the $ \mu$+jet channel for the nobtag subcategory with the BDT requirements selecting the most signallike events. The band includes statistical and systematic uncertainties. The background distributions are the results of the maximum likelihood fit. The signal distribution is multiplied by a factor of 5 to improve the readability. 
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Figure 3:
Expected and observed upper limits at 95% CL on the product of the scalar leptoninduced LQ production cross section and the branching fraction for a LQ coupled to b quarks and $ \tau $ leptons (left), or to lightflavor quarks and $ \tau $ leptons (right), using $ \lambda= $ 1.5. The theoretical cross sections correspond to the calculations of Refs. [40,41]. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of limits expected under the backgroundonly hypothesis. The filled circles show the observed limits for the combination of final states, while the other markers indicate the observed results per final state. 
png pdf 
Figure 3a:
Expected and observed upper limits at 95% CL on the product of the scalar leptoninduced LQ production cross section and the branching fraction for a LQ coupled to b quarks and $ \tau $ leptons, using $ \lambda= $ 1.5. The theoretical cross sections correspond to the calculations of Refs. [40,41]. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of limits expected under the backgroundonly hypothesis. The filled circles show the observed limits for the combination of final states, while the other markers indicate the observed results per final state. 
png pdf 
Figure 3b:
Expected and observed upper limits at 95% CL on the product of the scalar leptoninduced LQ production cross section and the branching fraction for a LQ coupled to lightflavor quarks and $ \tau $ leptons, using $ \lambda= $ 1.5. The theoretical cross sections correspond to the calculations of Refs. [40,41]. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of limits expected under the backgroundonly hypothesis. The filled circles show the observed limits for the combination of final states, while the other markers indicate the observed results per final state. 
png pdf 
Figure 4:
Upper limit at 95% CL on the coupling strength $ \lambda $ of a scalar LQ to b quarks and $ \tau $ leptons (left), and to lightflavor quarks and $ \tau $ leptons (right). Regions above the hatched lines are expected to be excluded. 
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Figure 4a:
Upper limit at 95% CL on the coupling strength $ \lambda $ of a scalar LQ to b quarks and $ \tau $ leptons. Regions above the hatched lines are expected to be excluded. 
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Figure 4b:
Upper limit at 95% CL on the coupling strength $ \lambda $ of a scalar LQ to lightflavor quarks and $ \tau $ leptons. Regions above the hatched lines are expected to be excluded. 
Tables  
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Table 1:
Selection criteria, where $ \ell $ stands for $ \tau_\mathrm{h} $, e, or $ \mu $, depending on the final state. 
Summary 
In summary, a search for leptoquarks produced in leptonquark collisions and coupled to $ \tau $ leptons has been performed for the first time, using data collected with the CMS detector in 20162018. These limits are complementary to those set using other production modes at high mass and coupling values for b$ \tau $ couplings, while the limits on the couplings of leptoquarks to lightflavor quarks extend the mass range excluded by previous searches in other production modes. 
Additional Figures  
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Additional Figure 1:
Observed and expected distributions of the collinear mass in the $ \tau_\mathrm{h}+ $ jet channels for the btag category with the lowest BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
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Additional Figure 2:
Observed and expected distributions of the collinear mass in the e $+ $ jet channels for the btag category with the lowest BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
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Additional Figure 3:
Observed and expected distributions of the collinear mass in the $ \mu+ $ jet channels for the btag category with the lowest BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 4:
Observed and expected distributions of the collinear mass in the $ \tau_\mathrm{h}+ $ jet channels for the btag category with intermediate BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
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Additional Figure 5:
Observed and expected distributions of the collinear mass in the e $+ $ jet channels for the btag category with intermediate BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 6:
Observed and expected distributions of the collinear mass in the $ \mu+ $ jet channels for the btag category with intermediate BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 7:
Observed and expected distributions of the collinear mass in the $ \tau_\mathrm{h}+ $ jet channels for the nobtag category with the lowest BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 8:
Observed and expected distributions of the collinear mass in the e $+ $ jet channels for the nobtag category with the lowest BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 9:
Observed and expected distributions of the collinear mass in the $ \mu+ $ jet channels for the nobtag category with the lowest BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 10:
Observed and expected distributions of the collinear mass in the $ \tau_\mathrm{h}+ $ jet channels for the nobtag category with low BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 11:
Observed and expected distributions of the collinear mass in the e $+ $ jet channels for the nobtag category with low BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 12:
Observed and expected distributions of the collinear mass in the $ \mu+ $ jet channels for the nobtag category with low BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 13:
Observed and expected distributions of the collinear mass in the $ \tau_\mathrm{h}+ $ jet channels for the nobtag category with intermediate BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 14:
Observed and expected distributions of the collinear mass in the e $+ $ jet channels for the nobtag category with intermediate BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 15:
Observed and expected distributions of the collinear mass in the $ \mu+ $ jet channels for the nobtag category with intermediate BDT output requirement. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 16:
Expected and observed upper limits at 95% CL on the scalar leptoninduced LQ production cross section times branching fraction for a LQ coupling to b quarks and $ \tau $ leptons using $ \lambda_{\mathrm{b}\tau}= $ 1.0. The bands around the predictions represent the theoretical uncertainties in the renormalization and factorization scales, and in the PDF. 
png pdf 
Additional Figure 17:
Expected and observed upper limits at 95% CL on the scalar leptoninduced LQ production cross section times branching fraction for a LQ coupling to b quarks and $ \tau $ leptons using $ \lambda_{\mathrm{b}\tau}= $ 2.0. The bands around the predictions represent the theoretical uncertainties in the renormalization and factorization scales, and in the PDF. 
png pdf 
Additional Figure 18:
Expected and observed upper limits at 95% CL on the scalar leptoninduced LQ production cross section times branching fraction for a LQ coupling to b quarks and $ \tau $ leptons using $ \lambda_{\mathrm{b}\tau}= $ 3.0. The bands around the predictions represent the theoretical uncertainties in the renormalization and factorization scales, and in the PDF. 
png pdf 
Additional Figure 19:
Expected and observed upper limits at 95% CL on the scalar leptoninduced LQ production cross section times branching fraction for a LQ coupling to lightflavor quarks and $ \tau $ leptons using $ \lambda_{\mathrm{q}\tau}= $ 0.5. The bands around the predictions represent the theoretical uncertainties in the renormalization and factorization scales, and in the PDF. 
png pdf 
Additional Figure 20:
Expected and observed upper limits at 95% CL on the scalar leptoninduced LQ production cross section times branching fraction for a LQ coupling to lightflavor quarks and $ \tau $ leptons using $ \lambda_{\mathrm{q}\tau}= $ 1.0. The bands around the predictions represent the theoretical uncertainties in the renormalization and factorization scales, and in the PDF. 
png pdf 
Additional Figure 21:
Expected and observed upper limits at 95% CL on the scalar leptoninduced LQ production cross section times branching fraction for a LQ coupling to lightflavor quarks and $ \tau $ leptons using $ \lambda_{\mathrm{q}\tau}= $ 2.0. The bands around the predictions represent the theoretical uncertainties in the renormalization and factorization scales, and in the PDF. 
png pdf 
Additional Figure 22:
Observed and expected distributions of the jet multiplicity in the e $+ $ jet channels for the btag CR with 0.2 $ < \Delta\phi(\mathrm{e},{\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) < $ 0.4. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
png pdf 
Additional Figure 23:
Observed and expected distributions of the jet multiplicity in the $ \mu+ $ jet channels for the btag CR with 0.2 $ < \Delta\phi(\mu,{\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) < $ 0.4. The uncertainty band includes statistical and systematic uncertainties, and the background distributions are the results of the maximum likelihood fit. 
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 elementaryparticle forces  PRL 32 (1974) 438  
3  S. Dimopoulos and L. Susskind  Mass without scalars  NPB 155 (1979) 237  
4  S. Dimopoulos  Technicoloured signatures  NPB 168 (1980) 69  
5  B. Schrempp and F. Schrempp  Light leptoquarks  PLB 153 (1985) 101  
6  W. Buchmüller and D. Wyler  Constraints on SU(5)type leptoquarks  PLB 177 (1986) 377  
7  B. Dumont, K. Nishiwaki, and R. Watanabe  LHC constraints and prospects for $ S_1 $ scalar leptoquark explaining the $ \overline B \to D^{(*)} \tau \bar\nu $ anomaly  PRD 94 (2016) 034001  1603.05248 
8  D. Buttazzo, A. Greljo, G. Isidori, and D. Marzocca  Bphysics anomalies: a guide to combined explanations  JHEP 11 (2017) 044  1706.07808 
9  J. Kumar, D. London, and R. Watanabe  Combined explanations of the $ b \to s \mu^+ \mu^ $ and $ b \to c \tau^ {\bar\nu} $ anomalies: a general model analysis  PRD 99 (2019) 015007  1806.07403 
10  A. Angelescu et al.  Single leptoquark solutions to the Bphysics anomalies  PRD 104 (2021) 055017  2103.12504 
11  ATLAS Collaboration  Search for new phenomena in $ pp $ collisions in final states with tau leptons, bjets, and missing transverse momentum with the ATLAS detector  PRD 104 (2021) 112005  2108.07665 
12  CMS Collaboration  Search for a singly produced thirdgeneration scalar leptoquark decaying to a $ \tau $ lepton and a bottom quark in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JHEP 07 (2018) 115  CMSEXO17029 1806.03472 
13  CMS Collaboration  Search for singly and pairproduced leptoquarks coupling to thirdgeneration fermions in protonproton collisions at $ \sqrt{s}= $ 13 TeV  PLB 819 (2021) 136446  CMSEXO19015 2012.04178 
14  ATLAS Collaboration  Search for pair production of thirdgeneration scalar leptoquarks decaying into a top quark and a $ \tau $lepton in $ pp $ collisions at $ \sqrt{s} $ = 13 TeV with the ATLAS detector  JHEP 06 (2021) 179  2101.11582 
15  CMS Collaboration  Searches for additional Higgs bosons and for vector leptoquarks in $ \tau\tau $ final states in protonproton collisions at $ \sqrt{s} $ = 13 TeV  Accepted by JHEP, 2022  CMSHIG21001 2208.02717 
16  CMS Collaboration  Search for new physics in the $ \tau $ lepton plus missing transverse momentum final state in protonproton collisions at $ \sqrt s $ = 13 TeV  Accepted by JHEP, 2022  CMSEXO21009 2212.12604 
17  ATLAS Collaboration  Search for excited $\tau $leptons and leptoquarks in the final state with $\tau $leptons and jets in pp collisions at $ \sqrt{s} $ = 13 tev with the ATLAS detector  JHEP 06 (2023) 199  2303.09444 
18  L. Buonocore, P. Nason, F. Tramontano, and G. Zanderighi  Leptons in the proton  JHEP 08 (2020) 019  2005.06477 
19  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 
20  A. V. Manohar, P. Nason, G. P. Salam, and G. Zanderighi  The photon content of the proton  JHEP 12 (2017) 046  1708.01256 
21  L. Buonocore et al.  Leptonquark collisions at the Large Hadron Collider  PRL 125 (2020) 231804  2005.06475 
22  U. Haisch and G. Polesello  Resonant thirdgeneration leptoquark signatures at the Large Hadron Collider  JHEP 05 (2021) 057  2012.11474 
23  A. Greljo and N. Selimovic  Leptonquark fusion at hadron colliders, precisely  JHEP 03 (2021) 279  2012.02092 
24  L. Buonocore et al.  Resonant leptoquark at NLO with POWHEG  JHEP 11 (2022) 129  2209.02599 
25  CMS Collaboration  HEPData record for this analysis  link  
26  CMS Collaboration  The CMS experiment at the CERN LHC  JINST 3 (2008) S08004  
27  CMS Collaboration  Performance of the CMS Level1 trigger in protonproton collisions at $ \sqrt{s} = $ 13 TeV  JINST 15 (2020) P10017  CMSTRG17001 2006.10165 
28  CMS Collaboration  The CMS trigger system  JINST 12 (2017) P01020  CMSTRG12001 1609.02366 
29  CMS Collaboration  Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC  JINST 16 (2021) P05014  CMSEGM17001 2012.06888 
30  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 
31  CMS Collaboration  Description and performance of track and primaryvertex reconstruction with the CMS tracker  JINST 9 (2014) P10009  CMSTRK11001 1405.6569 
32  CMS Collaboration  Particleflow reconstruction and global event description with the CMS detector  JINST 12 (2017) P10003  CMSPRF14001 1706.04965 
33  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  CMSTAU16003 1809.02816 
34  CMS Collaboration  Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV  JINST 12 (2017) P02014  CMSJME13004 1607.03663 
35  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 
36  CMS Collaboration  Identification of hadronic tau lepton decays using a deep neural network  JINST 17 (2022) P07023  CMSTAU20001 2201.08458 
37  M. Bahr et al.  Herwig++ physics and manual  EPJC 58 (2008) 639  0803.0883 
38  NNPDF Collaboration  Illuminating the photon content of the proton within a global PDF analysis  SciPost Phys. 5 (2018) 008  1712.07053 
39  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 
40  R. Frederix and S. Frixione  Merging meets matching in MC@NLO  JHEP 12 (2012) 061  1209.6215 
41  J. M. Lindert et al.  Precise predictions for V+jets dark matter backgrounds  EPJC 77 (2017) 829  1705.04664 
42  P. Nason  A new method for combining NLO QCD with shower Monte Carlo algorithms  JHEP 11 (2004) 040  hepph/0409146 
43  S. Frixione, P. Nason, and C. Oleari  Matching NLO QCD computations with parton shower simulations: the POWHEG method  JHEP 11 (2007) 070  0709.2092 
44  S. Alioli, P. Nason, C. Oleari, and E. Re  A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX  JHEP 06 (2010) 043  1002.2581 
45  S. Alioli et al.  Jet pair production in POWHEG  JHEP 04 (2011) 081  1012.3380 
46  S. Alioli, P. Nason, C. Oleari, and E. Re  NLO Higgs boson production via gluon fusion matched with shower in POWHEG  JHEP 04 (2009) 002  0812.0578 
47  T. Sjöstrand et al.  An introduction to PYTHIA 8.2  Comput. Phys. Commun. 191 (2015) 159  1410.3012 
48  CMS Collaboration  Extraction and validation of a new set of CMS PYTHIA 8 tunes from underlyingevent measurements  EPJC 80 (2020) 4  CMSGEN17001 1903.12179 
49  R. D. Ball et al.  Unbiased global determination of parton distributions and their uncertainties at NNLO and at LO  NPB 855 (2012) 153  1107.2652 
50  NNPDF Collaboration  Parton distributions with QED corrections  NPB 877 (2013) 290  1308.0598 
51  NNPDF Collaboration  Parton distributions from highprecision collider data  EPJC 77 (2017) 663  1706.00428 
52  GEANT4 Collaboration  GEANT 4  a simulation toolkit  NIM A 506 (2003) 250  
53  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 
54  M. Cacciari, G. P. Salam, and G. Soyez  The anti$ k_{\mathrm{T}} $ jet clustering algorithm  JHEP 04 (2008) 063  0802.1189 
55  CMS Collaboration  Jet algorithms performance in 13 TeV data  CMS Physics Analysis Summary, 2017 CMSPASJME16003 
CMSPASJME16003 
56  CMS Collaboration  Jet energy scale and resolution performance with 13 TeV data collected by CMS in 20162018  CMS Detector Performance Summary CMSDP2020019, 2020 CDS 

57  CMS Collaboration  Identification of heavyflavour jets with the CMS detector in pp collisions at 13 TeV  JINST 13 (2018) P05011  CMSBTV16002 1712.07158 
58  E. Bols et al.  Jet flavour classification using DeepJet  JINST 15 (2020) P12012  2008.10519 
59  R. Gavin, Y. Li, F. Petriello, and S. Quackenbush  W physics at the LHC with FEWZ 2.1  Comput. Phys. Commun. 184 (2013) 208  1201.5896 
60  R. Gavin, Y. Li, F. Petriello, and S. Quackenbush  FEWZ 2.0: A code for hadronic Z production at nexttonexttoleading order  Comput. Phys. Commun. 182 (2011) 2388  1011.3540 
61  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 
62  T. Gehrmann et al.  W$^+$W$^ $ production at hadron colliders in nexttonexttoleading order QCD  PRL 113 (2014) 212001  1408.5243 
63  J. Campbell, T. Neumann, and Z. Sullivan  Singletopquark production in the $ t $channel at NNLO  JHEP 02 (2021) 040  2012.01574 
64  N. Kidonakis and N. Yamanaka  Higherorder corrections for tW production at highenergy hadron colliders  JHEP 05 (2021) 278  2102.11300 
65  A. Höcker et al.  TMVA4  Toolkit for multivariate data analysis with ROOT. Users guide  physics/0703039  
66  CMS Collaboration  Measurements of inclusive W and Z cross sections in pp collisions at $ \sqrt{s}= $ 7 TeV  JHEP 01 (2011) 080  CMSEWK10002 1012.2466 
67  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 
68  CMS Collaboration  CMS luminosity measurement for the 2017 datataking period at $ \sqrt{s} = $ 13 TeV  CMS Physics Analysis Summary, 2018 CMSPASLUM17004 
CMSPASLUM17004 
69  CMS Collaboration  CMS luminosity measurement for the 2018 datataking period at $ \sqrt{s} = $ 13 TeV  CMS Physics Analysis Summary, 2019 CMSPASLUM18002 
CMSPASLUM18002 
70  T. Junk  Confidence level computation for combining searches with small statistics  NIM A 434 (1999) 435  hepex/9902006 
71  A. L. Read  Presentation of search results: the CL$_s $ technique  JPG 28 (2002) 2693  
72  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 