CMS-PAS-EXO-16-007

CMS-PAS-EXO-16-007
Search for pair-production of second-generation scalar leptoquarks in pp collisions at $\sqrt{s}=$ 13 TeV with the CMS detector
CMS Collaboration
March 2016

Abstract: A search is presented for pair-produced second-generation scalar leptoquarks, using 2.7 fb $^{-1}$ of data collected by the CMS detector during the 2015 proton-proton running of the LHC. A final state signature containing two high $p_{\mathrm{T}}$ muons and at least two jets is considered. Second generation scalar leptoquarks with masses less than 1165 (960) GeV are excluded when assuming the leptoquark branching fraction to a charged lepton and a quark $\beta=$ 1 ( $\beta=$ 0.5).
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ;

Figures & Tables	Additional Figures	References	CMS Publications

Figures
png pdf	Figure 1: Distributions of the muon and the jet ${p_{\mathrm {T}}}$ 's at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 1-a: Distributions of the first muon ${p_{\mathrm {T}}}$ 's at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 1-b: Distributions of the second muon ${p_{\mathrm {T}}}$ 's at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 1-c: Distributions of the first jet ${p_{\mathrm {T}}}$ 's at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 1-d: Distributions of the second jet ${p_{\mathrm {T}}}$ 's at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 2: Distributions of $S_{\mathrm{T}}$ , $M_{\mu \mu }$ , and of $M_{min}(\mu , {\mathrm {jet}})$ at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 2-a: Distribution of $S_{\mathrm{T}}$ at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 2-b: Distribution of $M_{\mu \mu }$ at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 2-c: Distribution of $M_{min}(\mu , {\mathrm {jet}})$ at preselection level. The contribution denoted as "Other Background" includes diboson, W+jets, and single-top contributions. Signal distributions are overlaid for LQ masses of 650 and 950 GeV.
png pdf	Figure 3: Expected and observed upper limits at 95% CL on the scalar leptoquark pair production cross section times $\beta ^2$ as a function of the second-generation scalar leptoquark mass. The expected limits and uncertainty bands represent the median expected limits and the 68% and 95% confidence intervals. The $\sigma _{\rm theory}$ curves and their bands represent, respectively, the theoretical scalar leptoquark pair production cross section and the uncertainties due to the choice of PDF and renormalization/factorization scales.

Tables
png pdf	Table 1: NLO cross-sections for the scalar LQ Monte Carlo sets used in the analysis.
png pdf	Table 2: Optimized thresholds for different signal mass hypotheses. All values are in GeV.
png pdf	Table 3: Event yields at final selection level, with signal yields given for $\beta =$ 1. Uncertainties are Poisson uncertainties on the MC background, except for the second uncertainty for "All BG", which gives the total systematic uncertainty as detailed in Section {systematics}. Systematic uncertainties are dominated by energy scale and shape uncertainties.

Additional Figures

png pdf

Additional Figure 1:
Expected and observed upper limits at 95% CL on the long-lived RPV SUSY

$\tilde{t}$ pair production cross section as a function of

$\tilde{t}$ mass (x-axis) and lifetime (y-axis). The expected limits and uncertainty bands represent the median expected limits and the 68% and 95% confidence intervals. Extrapolation has been performed to produce a limit plot down to the prompt kinematic range. On the right hand side, the expected and observed limits have been extrapolated to the prompt LQ limits at

$c\tau$ =0 cm, taking into account the different branching fractions to muons between the two models. This is motivated by the fact that once the

$\tilde{t}$ become prompt, they are nearly kinematically identical to LQs. The observed limit curve of the dedicated CMS search for displaced leptons in the e-mu channel (CMS EXO-16-022) has been overlaid.

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