CMSPASEXO17016  
Search for heavy neutrinos and thirdgeneration leptoquarks in final states with two hadronically decaying $\tau$ leptons and two jets in protonproton collisions at $\sqrt{s} = $ 13 TeV  
CMS Collaboration  
July 2018  
Abstract: A search for new particles has been conducted using events with two high transverse momentum ($p_{\textrm{T}}$) $\tau$ leptons that decay hadronically, at least two high$p_{\textrm{T}}$ jets, and missing transverse momentum from the $\tau$ lepton decays. The analysis is performed using data from protonproton collisions, collected by the CMS experiment at the LHC in 2016 at $\sqrt{s} = $ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{1}$. The observed data are consistent with the standard model expectation. The results are interpreted with two physics models. The first model involves righthanded charged bosons, $\textrm{W}_\mathrm{R}$, that decay to heavy righthanded neutrinos, $N_{\ell}$ ($\ell = \textrm{e}$, $\mu$, $\tau$), arising in a leftright symmetric extension of the standard model. The model considers that $\textrm{N}_{\textrm{e}}$ and $\textrm{N}_{\mu}$ are too heavy to be detected at the LHC. Assuming that the $\textrm{N}_{\tau}$ mass is half of the $\textrm{W}_\mathrm{R}$ mass, masses of the $\textrm{W}_\mathrm{R}$ boson below 3.5 TeV are excluded at a 95% confidence level (expected exclusion of 3.5 TeV). Exclusion bounds are also presented considering different scenarios for the mass ratio between $\textrm{N}_{\tau}$ and $\textrm{W}_\mathrm{R}$ as function of $\textrm{W}_\mathrm{R}$ mass. In the second model, pair production of thirdgeneration scalar leptoquarks that decay into $\tau\tau\textrm{b}\textrm{b}$ is considered, resulting in an observed (expected) exclusion region with leptoquark masses below 1.02 (1.0) TeV, assuming a 100% branching fraction for the leptoquark decay to a $\tau$ lepton and a bottom quark. These results represent the most stringent limits to date.  
Links:
CDS record (PDF) ;
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These preliminary results are superseded in this paper, JHEP 03 (2019) 170. The superseded preliminary plots can be found here. 
Figures  
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Figure 1:
Distributions in (left) $S^{MET}_{\textrm {T}}$, for the $\mathrm{ t \bar{t} } (\mu \mu \textrm {j j})$ control sample, and (right) $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1}, \textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (right) for the $\textrm {Z} (\tau \tau)$ control sample with relaxed $\tau _{\textrm {h}}$ $ p_{\textrm {T}} $ thresholds and $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2}) < $ 100 GeV. 
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Figure 1a:
Distributions in (left) $S^{MET}_{\textrm {T}}$, for the $\mathrm{ t \bar{t} } (\mu \mu \textrm {j j})$ control sample, and (right) $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1}, \textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (right) for the $\textrm {Z} (\tau \tau)$ control sample with relaxed $\tau _{\textrm {h}}$ $ p_{\textrm {T}} $ thresholds and $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2}) < $ 100 GeV. 
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Figure 1b:
Distributions in (left) $S^{MET}_{\textrm {T}}$, for the $\mathrm{ t \bar{t} } (\mu \mu \textrm {j j})$ control sample, and (right) $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1}, \textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (right) for the $\textrm {Z} (\tau \tau)$ control sample with relaxed $\tau _{\textrm {h}}$ $ p_{\textrm {T}} $ thresholds and $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2}) < $ 100 GeV. 
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Figure 2:
QCD multijet validation test in CR$B$ defined by $\textrm {N}_{\textrm {j}} \ge $ 2, $p_{\textrm {t}^{miss}} < $ 50 GeV, tight $\tau _{\textrm {h}}$ isolation, comparing the observed $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1},\textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (left) and $S_{\textrm {T}}^{MET}$ (right) shapes against extrapolation from the loose $\tau _{\textrm {h}}$ region, CR$A$. For both samples nonQCD contributions estimated from simulation have been subtracted, as discussed in the text. Note that the normalizations match by construction. The bottom frame shows the ratio between the observed "Data" in CR$B$ and the total background estimation. 
png pdf 
Figure 2a:
QCD multijet validation test in CR$B$ defined by $\textrm {N}_{\textrm {j}} \ge $ 2, $p_{\textrm {t}^{miss}} < $ 50 GeV, tight $\tau _{\textrm {h}}$ isolation, comparing the observed $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1},\textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (left) and $S_{\textrm {T}}^{MET}$ (right) shapes against extrapolation from the loose $\tau _{\textrm {h}}$ region, CR$A$. For both samples nonQCD contributions estimated from simulation have been subtracted, as discussed in the text. Note that the normalizations match by construction. The bottom frame shows the ratio between the observed "Data" in CR$B$ and the total background estimation. 
png pdf 
Figure 2b:
QCD multijet validation test in CR$B$ defined by $\textrm {N}_{\textrm {j}} \ge $ 2, $p_{\textrm {t}^{miss}} < $ 50 GeV, tight $\tau _{\textrm {h}}$ isolation, comparing the observed $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1},\textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (left) and $S_{\textrm {T}}^{MET}$ (right) shapes against extrapolation from the loose $\tau _{\textrm {h}}$ region, CR$A$. For both samples nonQCD contributions estimated from simulation have been subtracted, as discussed in the text. Note that the normalizations match by construction. The bottom frame shows the ratio between the observed "Data" in CR$B$ and the total background estimation. 
png pdf 
Figure 3:
Distributions in $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1},\textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (left) and $S_{T}^{MET}$ (right) for the estimated background in the signal region. The bottom frame shows the ratio between the observed data and the background estimation; the band corresponds to the statistical uncertainty for the background. The $\mathrm{ t \bar{t} }$, QCD multijet and \textrm {Z}+jets contributions are estimated employing MC and data driven techniques, while the other contributions are obtained from the MC prediction. 
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Figure 3a:
Distributions in $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1},\textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (left) and $S_{T}^{MET}$ (right) for the estimated background in the signal region. The bottom frame shows the ratio between the observed data and the background estimation; the band corresponds to the statistical uncertainty for the background. The $\mathrm{ t \bar{t} }$, QCD multijet and \textrm {Z}+jets contributions are estimated employing MC and data driven techniques, while the other contributions are obtained from the MC prediction. 
png pdf 
Figure 3b:
Distributions in $m(\tau _{\textrm {h},1},\tau _{\textrm {h},2},\textrm {j}_{1},\textrm {j}_{2},p_{\textrm {T}}^{\textrm {miss}})$ (left) and $S_{T}^{MET}$ (right) for the estimated background in the signal region. The bottom frame shows the ratio between the observed data and the background estimation; the band corresponds to the statistical uncertainty for the background. The $\mathrm{ t \bar{t} }$, QCD multijet and \textrm {Z}+jets contributions are estimated employing MC and data driven techniques, while the other contributions are obtained from the MC prediction. 
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Figure 4:
Upper limits at the 95% confidence level on the cross section times branching fraction for production of (above) $\textrm {W}_{\textrm {R}}$ decaying to $\textrm {N}_{\tau}$ and (below) a pair of leptoquarks each decaying to $\tau \textrm {b}$, as functions of the produced particle mass. The observed limits are shown as solid black lines. Expected limits and their one (two) standard deviation limits are shown by dashed lines with green (yellow) bands. The theoretical cross sections are indicated by the solid blue lines. 
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Figure 4a:
Upper limits at the 95% confidence level on the cross section times branching fraction for production of (above) $\textrm {W}_{\textrm {R}}$ decaying to $\textrm {N}_{\tau}$ and (below) a pair of leptoquarks each decaying to $\tau \textrm {b}$, as functions of the produced particle mass. The observed limits are shown as solid black lines. Expected limits and their one (two) standard deviation limits are shown by dashed lines with green (yellow) bands. The theoretical cross sections are indicated by the solid blue lines. 
png pdf 
Figure 4b:
Upper limits at the 95% confidence level on the cross section times branching fraction for production of (above) $\textrm {W}_{\textrm {R}}$ decaying to $\textrm {N}_{\tau}$ and (below) a pair of leptoquarks each decaying to $\tau \textrm {b}$, as functions of the produced particle mass. The observed limits are shown as solid black lines. Expected limits and their one (two) standard deviation limits are shown by dashed lines with green (yellow) bands. The theoretical cross sections are indicated by the solid blue lines. 
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Figure 5:
Expected and observed limits at the 95% confidence level as a function of $m(\textrm {W}_{\textrm {R}})$ and $x=m(\textrm {N}_{\tau})/m(\textrm {W}_{\textrm {R}})$. 
Tables  
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Table 1:
Summary of systematic uncertainties. Values are given in percent. "s'' indicates a shape uncertainty. For example, "12,s" means the normalization uncertainty is 12%, but varied mass and $S_{\textrm {T}}^{MET}$ distributions are also considered to account for shape systematics. These varied mass and $S_{\textrm {T}}^{MET}$ distributions are normalized to the predicted background yields outlined in Section 6 and Table xxxxx. 
png pdf 
Table 2:
Estimated prefit background and signal yields in the SR and their statistical uncertainties. The \textrm {Z}+jets and $\mathrm{ t \bar{t} }$ background normalizations are determined by correcting the predictions obtained from the simulated samples with scale factors, $SF^{\textrm {Z}\to \mu \mu}_{dijet}$ and $SF^{\mathrm{ t \bar{t} }}$, determined in dedicated data control samples. The QCD multijet background event rate is determined with a datadriven method utilizing the number of QCD multijet events containing two nonisolated $\tau _{\textrm {h}}$ candidates and scaled by the TL ratio. The expected number of events for the $ {\mathrm {W}}_\mathrm {R}$ signal sample assume $m(\textrm {N}_{\tau}) = m({\mathrm {W}}_\mathrm {R})/2$. 
Summary 
A search is performed for physics beyond the standard model (BSM) in events with two energetic $\tau$ leptons, two energetic jets, and large momentum imbalance, using data corresponding to an integrated luminosity of 35.9 fb$^{1}$ collected in 2016 by the CMS detector in protonproton collisions at $\sqrt{s}= $ 13 TeV. The search focuses on two benchmark scenarios: (1) production of heavy righthanded neutrinos, $\textrm{N}_{\ell}$, and righthanded $\textrm{W}_{\textrm{R}}$ bosons, which arise in the leftright symmetric extensions of the SM and where the $\textrm{W}_{\textrm{R}}$ and $\textrm{N}_{\ell}$ decay chains result in a pair of hightransverse momentum $\tau$ leptons; (2) pair production of thirdgeneration scalar leptoquarks that decay to $\tau\tau$\textrm{bb}. The observed $m(\tau_{\textrm{h},1},\tau_{\textrm{h},2},\textrm{j}_{1},\textrm{j}_{2},p_{\textrm{T}}^{\textrm{miss}})$ and $S^{MET}_{\textrm{T}}$ distributions do not reveal any evidence for physics beyond the SM. Assuming that only the $\textrm{N}_{\tau}$ flavor contributes significantly to the $\mathrm{W}_\mathrm{R}$ decay width, $\mathrm{W}_\mathrm{R}$ masses below 3.45 (2.75) TeV are excluded at the 95% confidence level, assuming the $\textrm{N}_{\tau}$ mass is 0.8 (0.2) times the mass of $\mathrm{W}_\mathrm{R}$ boson. In the second BSM scenario, leptoquarks with a mass less than 1.02 TeV are excluded at the 95% confidence level, to be compared with an expected mass limit of 1.00 TeV. Both of these results represent the most stringent limits to date in $\tau \tau \textrm{j} \textrm{j}$ final states, exceeding the previous limits by CMS using 12.9 fb$^{1}$ of data recorded at 13 TeV [48]. 
References  
1  M. Lindner, T. Ohlsson, and G. Seidl  Seesaw mechanisms for Dirac and Majorana neutrino masses  PRD 65 (2002) 053014  hepph/0109264 
2  P. Minkowski  $ \mu \to e\gamma $ at a Rate of One Out of $ 10^{9} $ Muon Decays?  PLB 67 (1977) 421428  
3  R. N. Mohapatra and G. Senjanovic  Neutrino Mass and Spontaneous Parity Violation  PRL 44 (1980) 912  
4  J. C. Pati and A. Salam  Unified leptonhadron symmetry and a gauge theory of the basic interactions  PRD 8 (1973) 1240  
5  J. C. Pati and A. Salam  Lepton number as the fourth color  PRD 10 (1974) 275, . [Erratum: \DOI10.1103/PhysRevD.11.703.2]  
6  H. Georgi and S. L. Glashow  Unity of all elementary particle forces  PRL 32 (1974) 438  
7  H. Fritzsch and P. Minkowski  Unified interactions of leptons and hadrons  Ann. Phys. 93 (1975) 193  
8  S. Dimopoulos and L. Susskind  Mass without scalars  NPB 155 (1979) 237  
9  S. Dimopoulos  Technicolored signatures  NPB 168 (1980) 69  
10  E. Farhi and L. Susskind  Technicolor  PR 74 (1981) 277  
11  K. D. Lane and M. V. Ramana  Walking technicolor signatures at hadron colliders  PRD 44 (1991) 2678  
12  B. Schrempp and F. Schrempp  Light leptoquarks  PLB 153 (1985) 101  
13  B. Gripaios  Composite leptoquarks at the LHC  JHEP 02 (2010) 045  0910.1789 
14  G. R. Farrar and P. Fayet  Phenomenology of the production, decay, and detection of new hadronic states associated with supersymmetry  PLB 76 (1978) 575  
15  P. Ramond  Dual theory for free fermions  PRD 3 (1971) 2415  
16  Y. A. Golfand and E. P. Likhtman  Extension of the algebra of Poincar$ \'e $ group generators and violation of p invariance  JEPTL 13 (1971)323  
17  A. Neveu and J. H. Schwarz  Factorizable dual model of pions  NPB 31 (1971) 86  
18  D. V. Volkov and V. P. Akulov  Possible universal neutrino interaction  JEPTL 16 (1972)438  
19  J. Wess and B. Zumino  A Lagrangian model invariant under supergauge transformations  PLB 49 (1974) 52  
20  J. Wess and B. Zumino  Supergauge transformations in four dimensions  NPB 70 (1974) 39  
21  P. Fayet  Supergauge invariant extension of the Higgs mechanism and a model for the electron and its neutrino  NPB 90 (1975) 104  
22  H. P. Nilles  Supersymmetry, supergravity and particle physics  PR 110 (1984) 1  
23  R. Barbier et al.  Rparity violating supersymmetry  PR 420 (2005) 1  hepph/0406039 
24  J. Pati and A. Salam  Lepton number as the fourth color  PRD 10 (1974) 275  
25  B. Gripaios  Composite leptoquarks at the lhc  JHEP 02 (2010) 045  
26  W. Buchmuller and D. Wyler  Constraints on SU(5)type leptoquarks  PLB 177 (1986) 377  
27  O. U. Shanker  $ \pi \ell $2, $ K \ell $3 and $ K^0  \bar{K}^{0} $ constraints on leptoquarks and supersymmetric particles  NPB 204 (1982) 375  
28  BaBar Collaboration  Evidence for an excess of $ \bar{B} \to D^{(*)} \tau^\bar{\nu}_\tau $ decays  PRL 109 (2012) 101802  1205.5442 
29  BaBar Collaboration  Measurement of an excess of $ \bar{B} \to D^{(*)}\tau^ \bar{\nu}_\tau $ decays and implications for charged Higgs bosons  PRD 88 (2013) 072012  1303.0571 
30  Belle Collaboration  Observation of $ B^0 \to D^{*} \tau^+ \nu_\tau $ decay at Belle  PRL 99 (2007) 191807  0706.4429 
31  Belle Collaboration  Observation of $ B^+ \to \bar{D}^{*0} \tau^+ \nu_\tau $ and evidence for $ B^+ \to \bar{D}^0 \tau^+ \nu_\tau $ at Belle  PRD 82 (2010) 072005  1005.2302 
32  Belle Collaboration  Measurement of the branching ratio of $ \bar{B} \to D^{(\ast)} \tau^ \bar{\nu}_\tau $ relative to $ \bar{B} \to D^{(\ast)} \ell^ \bar{\nu}_\ell $ decays with hadronic tagging at Belle  PRD 92 (2015) 072014  1507.03233 
33  Belle Collaboration  Measurement of the $ \tau $ lepton polarization and $ R(D^*) $ in the decay $ \bar{B} \to D^* \tau^ \bar{\nu}_\tau $  PRL 118 (2017) 211801  1612.00529 
34  LHCb Collaboration  Measurement of formfactorindependent observables in the decay $ B^{0} \to K^{*0} \mu^+ \mu^ $  PRL 111 (2013) 191801  1308.1707 
35  LHCb Collaboration  Test of lepton universality using $ B^{+}\rightarrow K^{+}\ell^{+}\ell^{} $ decays  PRL 113 (2014) 151601  1406.6482 
36  LHCb Collaboration  Measurement of the ratio of branching fractions $ \mathcal{B}(\bar{B}^0 \to D^{*+}\tau^{}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}^0 \to D^{*+}\mu^{}\bar{\nu}_{\mu}) $  PRL 115 (2015) 111803  1506.08614 
37  LHCb Collaboration  Angular analysis of the $ B^{0} \to K^{*0} \mu^{+} \mu^{} $ decay using 3 fb$ ^{1} $ of integrated luminosity  JHEP 02 (2016) 104  1512.04442 
38  LHCb Collaboration  Test of lepton universality with $ B^{0} \rightarrow K^{*0}\ell^{+}\ell^{} $ decays  JHEP 08 (2017) 055  1705.05802 
39  M. Tanaka and R. Watanabe  New physics in the weak interaction of $ \bar B\to D^{(*)}\tau\bar\nu $  PRD 87 (2013) 034028  1212.1878 
40  Y. Sakaki, M. Tanaka, A. Tayduganov, and R. Watanabe  Testing leptoquark models in $ \bar B \to D^{(*)} \tau \bar\nu $  PRD 88 (2013) 094012  1309.0301 
41  I. Dor\vsner, S. Fajfer, N. Ko\vsnik, and I. Ni\vsand\vzi\'c  Minimally flavored colored scalar in $ \bar B \to D^{(*)} \tau \bar \nu $ and the mass matrices constraints  JHEP 11 (2013) 084  1306.6493 
42  B. Gripaios, M. Nardecchia, and S. A. Renner  Composite leptoquarks and anomalies in $ B $meson decays  JHEP 05 (2015) 006  1412.1791 
43  ATLAS Collaboration  Search for heavy neutrinos and righthanded $ W $ bosons in events with two leptons and jets in $ pp $ collisions at $ \sqrt{s}= $ 7 TeV with the ATLAS detector  EPJC 72 (2012) 2056  1203.5420 
44  ATLAS Collaboration  Search for heavy Majorana neutrinos with the ATLAS detector in pp collisions at $ \sqrt{s}= $ 8 TeV  JHEP 07 (2015) 162  1506.06020 
45  ATLAS Collaboration  Search for third generation scalar leptoquarks in pp collisions at $ \sqrt{s} = $ 7 TeV with the ATLAS detector  JHEP 06 (2013) 033  1303.0526 
46  CMS Collaboration  Search for a heavy righthanded W boson and a heavy neutrino in events with two sameflavor leptons and two jets at $ \sqrt{s} = $ 13 TeV  JHEP 05 (2018) 148  CMSEXO17011 1803.11116 
47  CMS Collaboration  Search for a heavy composite Majorana neutrino in the final state with two leptons and two quarks at $ \sqrt{s} = $ 13 TeV  CMSEXO16026 1706.08578 

48  CMS Collaboration  Search for thirdgeneration scalar leptoquarks and heavy righthanded neutrinos in final states with two tau leptons and two jets in protonproton collisions at $ \sqrt{s}= $ 13 TeV  JHEP 07 (2017) 121  CMSEXO16023 1703.03995 
49  CMS Collaboration  Search for heavy neutrinos or thirdgeneration leptoquarks in final states with two hadronically decaying $ \tau $ leptons and two jets in protonproton collisions at $ \sqrt{s}= $ 13 TeV  JHEP 03 (2017) 077  CMSEXO16016 1612.01190 
50  CMS Collaboration  Search for thirdgeneration scalar leptoquarks decaying to a top quark and a $ \tau $ lepton at $ \sqrt{s}= $ 13 TeV  Submitted to \it EPJC  CMSB2G16028 1803.02864 
51  CMS Collaboration  Constraints on models of scalar and vector leptoquarks decaying to a quark and a neutrino at $ \sqrt{s}= $ 13 TeV  CMSSUS18001 1805.10228 

52  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  CMSEXO17029 1806.03472 

53  CMS Collaboration  Search for heavy neutrinos and $ \mathrm {W} $ bosons with righthanded couplings in protonproton collisions at $ \sqrt{s} = $ 8 TeV  EPJC 74 (2014) 3149  CMSEXO13008 1407.3683 
54  CMS Collaboration  The CMS experiment at the CERN LHC  JINST 03 (2008) S08004  CMS00001 
55  CMS Collaboration  Particleflow reconstruction and global event description with the cms detector  JINST 12 (2017) P10003  CMSPRF14001 1706.04965 
56  M. Cacciari, G. P. Salam, and G. Soyez  The anti$ {k_{\mathrm{T}}} $ jet clustering algorithm  JHEP 04 (2008) 063  0802.1189 
57  CMS Collaboration  Jet algorithms performance in 13 TeV data  CMSPASJME16003  CMSPASJME16003 
58  CMS Collaboration  Determination of jet energy calibration and transverse momentum resolution in CMS  JINST 6 (2011) 11002  CMSJME10011 1107.4277 
59  CMS Collaboration  Study of pileup removal algorithms for jets  CMSPASJME14001  CMSPASJME14001 
60  CMS Collaboration  Identification of heavyflavour jets with the CMS detector in pp collisions at 13 TeV  JINST 13 (2018) P05011  CMSBTV16002 1712.07158 
61  CMS Collaboration  Performance of electron reconstruction and selection with the CMS detector in protonproton collisions at $ \sqrt{s} = $ 8 TeV  JINST 10 (2015) P06005  CMSEGM13001 1502.02701 
62  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 
63  CMS Collaboration  Performance of $ \tau $lepton reconstruction and identification in CMS  JINST \bf 07 (2012) P01001  
64  CMS Collaboration Collaboration  Performance of reconstruction and identification of tau leptons in their decays to hadrons and tau neutrino in LHC Run2  CMSPASTAU16002, CERN, Geneva  
65  CMS Collaboration  Performance of missing energy reconstruction in 13 TeV pp collision data using the CMS detector  CMSPASJME16004  CMSPASJME16004 
66  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 
67  T. Sjostrand et al.  An introduction to PYTHIA 8.2  CPC 191 (2015) 159  1410.3012 
68  M. Kramer, T. Plehn, M. Spira, and P. M. Zerwas  Pair production of scalar leptoquarks at the CERN LHC  PRD 71 (2005) 057503  
69  F. del Aguila, J. A. AguilarSaavedra, and R. Pittau  Heavy neutrino signals at large hadron colliders  JHEP 10 (2007) 047  hepph/0703261 
70  J. Pumplin et al.  New generation of parton distributions with uncertainties from global QCD analysis  JHEP 07 (2002) 012  hepph/0201195 
71  CMS Collaboration  Measurement of the inclusive Z cross section via decays to tau pairs in pp collisions at $ \sqrt{s} = $ 7 TeV  JHEP 08 (2011) 117  
72  ATLAS Collaboration  A search for prompt leptonjets in $ pp $ collisions at $ \sqrt{s} = $ 8 TeV with the atlas detector  JHEP 02 (2016) 062  
73  CMS Collaboration Collaboration  CMS Luminosity Measurements for the 2016 Data Taking Period  CMSPASLUM17001, CERN, Geneva  
74  S. Alekhin et al.  The PDF4LHC Working Group Interim Report  1101.0536  
75  M. Botje et al.  The PDF4LHC Working Group Interim Recommendations  1101.0538  
76  P. M. Nadolsky et al.  Implications of CTEQ global analysis for collider observables  PRD 78 (2008) 013004  0802.0007 
77  A. D. Martin, W. J. Stirling, R. S. Thorne, and G. Watt  Update of parton distributions at NNLO  PLB 652 (2007) 292  
78  M. Ubiali  NNPDF1.0 parton set for the LHC  NPPS 186 (2009) 62  
79  T. Junk  Confidence level computation for combining searches with small statistics  NIMA 434 (1999) 435  hepex/9902006 
80  A. L. Read  Presentation of search results: the $ CL_s $ technique  JPG 28 (2002) 2693  
81  ATLAS and CMS Collaborations  Procedure for the LHC Higgs boson search combination in Summer 2011  CMSNOTE2011005  
82  R. J. Barlow and C. Beeston  Fitting using finite Monte Carlo samples  CPC 77 (1993)  
83  M. Kramer, T. Plehn, M. Spira, and P. M. Zerwas  Pair production of scalar leptoquarks at the CERN LHC  PRD 71 (2005) 057503  hepph/0411038 
Compact Muon Solenoid LHC, CERN 