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| CMS-PAS-FTR-18-008 | ||
| Projection of searches for pair production of scalar leptoquarks decaying to a top quark and a charged lepton at the HL-LHC | ||
| CMS Collaboration | ||
| November 2018 | ||
| Abstract: Projections for searches for pair-produced scalar leptoquarks decaying into top quarks and muons or tau leptons for high integrated luminosities of up to 3000 fb$^{-1}$ at the high luminosity LHC are presented. This study is based on published analysis results of data recorded in the year 2016. It uses scaled signal and background templates to estimate the reach in terms of discovery potential and upper limits on the leptoquark pair production cross section. Two different ways of treating systematic uncertainties are studied. The mass reach for a 5$\sigma$ discovery or a 95% confidence level exclusion is expected to increase by 400 to 500 GeV with respect to the 2016 results. In the case of mixed decays between these two channels, the mass expected to be in reach for a 5$\sigma$ discovery and the expected 95% confidence level limit on excluded leptoquark masses ranges from 1200 to 1700 GeV and from 1400 to 1900 GeV depending on the value of the branching fraction, respectively. | ||
| Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1:
Feynman diagrams of the gluon-induced production and the subsequent decay of a pair of LQs into top quarks and muons (left) and into top quarks and $\tau $ leptons with a subsequent decay of the two top quarks into the $\ell $+jets final state (right), where $\ell $ denotes an electron or muon. |
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Figure 1-a:
Feynman diagram of the gluon-induced production and the subsequent decay of a pair of LQs into top quarks and muons. |
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Figure 1-b:
Feynman diagram of the gluon-induced production and the subsequent decay of a pair of LQs into top quarks and $\tau $ leptons with a subsequent decay of the two top quarks into the $\ell $+jets final state, where $\ell $ denotes an electron or muon. |
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Figure 2:
Expected significances for an LQ decaying exclusively to top quarks and muons (left) or $\tau $ leptons (right) as a function of the LQ mass and for different integrated luminosities in the ''YR18 syst.'' (solid) and ''stat. only'' (dotted) scenarios. All results were obtained with templates for $\sqrt {s} = $ 13 TeV that were scaled to $\sqrt {s} = $ 14 TeV. |
png pdf |
Figure 2-a:
Expected significances for an LQ decaying exclusively to top quarks and muons as a function of the LQ mass and for different integrated luminosities in the ''YR18 syst.'' (solid) and ''stat. only'' (dotted) scenarios. All results were obtained with templates for $\sqrt {s} = $ 13 TeV that were scaled to $\sqrt {s} = $ 14 TeV. |
png pdf |
Figure 2-b:
Expected significances for an LQ decaying exclusively to top quarks and $\tau $ leptons as a function of the LQ mass and for different integrated luminosities in the ''YR18 syst.'' (solid) and ''stat. only'' (dotted) scenarios. All results were obtained with templates for $\sqrt {s} = $ 13 TeV that were scaled to $\sqrt {s} = $ 14 TeV. |
png pdf |
Figure 3:
Expected upper limits on the LQ pair production cross section at the 95% CL for an LQ decaying exclusively to top quarks and muons (left) or $\tau $ leptons (right) as a function of the LQ mass and for different integrated luminosities in the ''YR18 syst.'' (solid) and ''stat. only'' (dotted) scenarios. All results were obtained with templates for $\sqrt {s} = $ 13 TeV that were scaled to $\sqrt {s} = $ 14 TeV. The LQ pair production cross section was calculated at NLO [35], its uncertainty takes into account PDF and scale variations. |
png pdf |
Figure 3-a:
Expected upper limits on the LQ pair production cross section at the 95% CL for an LQ decaying exclusively to top quarks and muons as a function of the LQ mass and for different integrated luminosities in the ''YR18 syst.'' (solid) and ''stat. only'' (dotted) scenarios. All results were obtained with templates for $\sqrt {s} = $ 13 TeV that were scaled to $\sqrt {s} = $ 14 TeV. The LQ pair production cross section was calculated at NLO [35], its uncertainty takes into account PDF and scale variations. |
png pdf |
Figure 3-b:
Expected upper limits on the LQ pair production cross section at the 95% CL for an LQ decaying exclusively to top quarks and $\tau $ leptons as a function of the LQ mass and for different integrated luminosities in the ''YR18 syst.'' (solid) and ''stat. only'' (dotted) scenarios. All results were obtained with templates for $\sqrt {s} = $ 13 TeV that were scaled to $\sqrt {s} = $ 14 TeV. The LQ pair production cross section was calculated at NLO [35], its uncertainty takes into account PDF and scale variations. |
png pdf |
Figure 4:
Expected significances (left) and expected upper limits on the LQ pair-production cross section at the 95% CL (right) as a function of the LQ mass and the branching fraction at 3000 fb$^{-1}$ in the ''YR18 syst.'' and the ''stat. only'' scenarios. Color-coded lines represent lines of a constant expected significance or cross section limit, respectively. The red lines indicate the 5$\sigma $ discovery level (left) and the mass exclusion limit (right). |
png pdf |
Figure 4-a:
Expected significances as a function of the LQ mass and the branching fraction at 3000 fb$^{-1}$ in the ''YR18 syst.'' and the ''stat. only'' scenarios. Color-coded lines represent lines of a constant expected significance. The red lines indicate the 5$\sigma $ discovery level. |
png pdf |
Figure 4-b:
Expected upper limits on the LQ pair-production cross section at the 95% CL as a function of the LQ mass and the branching fraction at 3000 fb$^{-1}$ in the ''YR18 syst.'' and the ''stat. only'' scenarios. Color-coded lines represent lines of a constant expected cross section limit. The red lines indicate the mass exclusion limit. |
| Tables | |
png pdf |
Table 1:
Scaled relative systematic uncertainties in the ''YR18 syst.'' scenario at $\mathcal {L}_{\text {int}}^{\text {target}}= $ 3000 fb$^{-1} $. |
| Summary |
| Projections for searches for pair production of scalar leptoquarks decaying into top quarks and muons or $\tau$ leptons at the high-luminosity LHC have been presented. They are based on published analyses of the dataset recorded by the CMS experiment in 2016. The effect of an increased center-of-mass energy of $\sqrt{s} = $ 14 TeV and the impact of reduced systematic uncertainties have been taken into account. The results of the analyses of the 2016 dataset are expected to be improved significantly with an integrated luminosity of 3000 fb$^{-1}$. |
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