CMS-SUS-21-005

CMS-SUS-21-005 ; CERN-EP-2026-130
Search for new physics using single-lepton events with high multiplicities of jets and b jets in proton-proton collisions at $ \sqrt{s}= $ 13 TeV
CMS Collaboration
8 June 2026
Submitted to the Journal of High Energy Physics
Abstract: This paper presents a search for beyond the standard model physics using single-lepton events with a high multiplicity of jets, including those identified as bottom quark jets, without a requirement on missing transverse momentum. The analysis is based on proton-proton collision data collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. This search is sensitive to $ R $-parity violating supersymmetry models, where supersymmetric particles can decay into standard-model particles through interactions that violate baryon number conservation. In particular, the signal model considered is gluino pair production, where each gluino decays into top, bottom, and strange quarks. The sum of large-radius jet masses is used to distinguish the signal from background, as it effectively captures the features of high jet multiplicity and high interaction energy. No significant excess of data over the background predictions is observed. Gluinos in this model have been excluded for masses below 1890 GeV at 95% confidence level.
Links: e-print arXiv:2606.09567 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Diagram of the signal model considered in this analysis. Gluinos are produced in pairs and decay to t, b, and s.
png pdf	Figure 2: Distributions of $ N_{\text{jet}} $ (left), $ N_{\mathrm{b}} $ (middle), and $ M_{\mathrm{J}} $ (right) for $ {\mathrm{t}\overline{\mathrm{t}}} $ and signal events in two gluino mass scenarios, after applying the baseline selection, as described in Section 3.
png pdf	Figure 2-a: Distributions of $ N_{\text{jet}} $ (left), $ N_{\mathrm{b}} $ (middle), and $ M_{\mathrm{J}} $ (right) for $ {\mathrm{t}\overline{\mathrm{t}}} $ and signal events in two gluino mass scenarios, after applying the baseline selection, as described in Section 3.
png pdf	Figure 2-b: Distributions of $ N_{\text{jet}} $ (left), $ N_{\mathrm{b}} $ (middle), and $ M_{\mathrm{J}} $ (right) for $ {\mathrm{t}\overline{\mathrm{t}}} $ and signal events in two gluino mass scenarios, after applying the baseline selection, as described in Section 3.
png pdf	Figure 2-c: Distributions of $ N_{\text{jet}} $ (left), $ N_{\mathrm{b}} $ (middle), and $ M_{\mathrm{J}} $ (right) for $ {\mathrm{t}\overline{\mathrm{t}}} $ and signal events in two gluino mass scenarios, after applying the baseline selection, as described in Section 3.
png pdf	Figure 3: Comparison of $ M_{\mathrm{J}} $ shapes between data and simulation in the CRs used to measure the $ \kappa $ factors for QCD multijet (left), W+jets (middle), and $ {\mathrm{t}\overline{\mathrm{t}}} $ (right). The selection corresponds to $ N_{\text{lep}}= $ 0, $ N_{\text{jet}}\ge $ 9, $ N_{\mathrm{b}}= $ 0 for QCD multijet; a DY+jets background dominated region with $ N_{\text{lep}}= $ 2, $ N_{\text{jet}}\ge $ 7, $ N_{\mathrm{b}}\le $ 2 for W+jets; and $ N_{\text{lep}}= $ 1, $ N_{\text{jet}}\ge $ 8, $ N_{\mathrm{b}}= $ 1 for $ {\mathrm{t}\overline{\mathrm{t}}} $. The simulation is normalized to data in all regions.
png pdf	Figure 3-a: Comparison of $ M_{\mathrm{J}} $ shapes between data and simulation in the CRs used to measure the $ \kappa $ factors for QCD multijet (left), W+jets (middle), and $ {\mathrm{t}\overline{\mathrm{t}}} $ (right). The selection corresponds to $ N_{\text{lep}}= $ 0, $ N_{\text{jet}}\ge $ 9, $ N_{\mathrm{b}}= $ 0 for QCD multijet; a DY+jets background dominated region with $ N_{\text{lep}}= $ 2, $ N_{\text{jet}}\ge $ 7, $ N_{\mathrm{b}}\le $ 2 for W+jets; and $ N_{\text{lep}}= $ 1, $ N_{\text{jet}}\ge $ 8, $ N_{\mathrm{b}}= $ 1 for $ {\mathrm{t}\overline{\mathrm{t}}} $. The simulation is normalized to data in all regions.
png pdf	Figure 3-b: Comparison of $ M_{\mathrm{J}} $ shapes between data and simulation in the CRs used to measure the $ \kappa $ factors for QCD multijet (left), W+jets (middle), and $ {\mathrm{t}\overline{\mathrm{t}}} $ (right). The selection corresponds to $ N_{\text{lep}}= $ 0, $ N_{\text{jet}}\ge $ 9, $ N_{\mathrm{b}}= $ 0 for QCD multijet; a DY+jets background dominated region with $ N_{\text{lep}}= $ 2, $ N_{\text{jet}}\ge $ 7, $ N_{\mathrm{b}}\le $ 2 for W+jets; and $ N_{\text{lep}}= $ 1, $ N_{\text{jet}}\ge $ 8, $ N_{\mathrm{b}}= $ 1 for $ {\mathrm{t}\overline{\mathrm{t}}} $. The simulation is normalized to data in all regions.
png pdf	Figure 3-c: Comparison of $ M_{\mathrm{J}} $ shapes between data and simulation in the CRs used to measure the $ \kappa $ factors for QCD multijet (left), W+jets (middle), and $ {\mathrm{t}\overline{\mathrm{t}}} $ (right). The selection corresponds to $ N_{\text{lep}}= $ 0, $ N_{\text{jet}}\ge $ 9, $ N_{\mathrm{b}}= $ 0 for QCD multijet; a DY+jets background dominated region with $ N_{\text{lep}}= $ 2, $ N_{\text{jet}}\ge $ 7, $ N_{\mathrm{b}}\le $ 2 for W+jets; and $ N_{\text{lep}}= $ 1, $ N_{\text{jet}}\ge $ 8, $ N_{\mathrm{b}}= $ 1 for $ {\mathrm{t}\overline{\mathrm{t}}} $. The simulation is normalized to data in all regions.
png pdf	Figure 4: The $ \kappa $ factors measured in control regions for the QCD multijet (yellow left), W+jets (purple middle), and $ {\mathrm{t}\overline{\mathrm{t}}} $ (blue right) backgrounds. The upper and lower panels correspond to $ \kappa_1 $ and $ \kappa_2 $, respectively. In each case, the three points indicate the $ \kappa $ values in each $ N_{\text{jet}} $ bin. The error bars include the statistical uncertainties of data (dominant) and MC simulation samples.
png pdf	Figure 5: Background-only post-fit $ M_{\mathrm{J}} $ distributions in the $ N_{\text{lep}}= $ 1 region for all three data-taking years, with pre-fit signal overlaid. The three $ M_{\mathrm{J}} $ bins used, defined as 500 $ < M_{\mathrm{J}} < $ 800, 800 $ < M_{\mathrm{J}} < $ 1100, and $ M_{\mathrm{J}} > $ 1100 GeV, are shown from left to right. The data-to-simulation ratio is shown in the lower panel, where the hatched band represents the total (statistical and systematic) uncertainty in the background prediction.
png pdf	Figure 6: Cross section upper limits at 95% CL compared to the predicted cross section of gluino pair production with $ \mathrm{\widetilde{g}}\to\mathrm{t}\mathrm{b}\mathrm{s} $ (magenta). The theoretical uncertainties in the cross section are represented by the dotted band corresponding to ${\pm}$1 standard deviation (s.d.). The expected limits are shown by the black dashed line, with 68% and 95% CL variations indicated by the green inner and yellow outer bands, respectively. The observed limit is shown as a black solid line with dots.

Tables
png pdf	Table 1: A diagram representing the analysis regions after the baseline selection. Here, ``CR'' denotes a control region and ``SR'' denotes a signal region. Darker yellow indicates regions where the $ M_{\mathrm{J}} $ template is used, while lighter yellow corresponds to regions where it is not used.
png pdf	Table 2: Selection criteria applied for measuring the $ \kappa $ factors of the main backgrounds.
png pdf	Table 3: Uncertainties in the $ \kappa $ factors for QCD multijet, W+jets, and $ {\mathrm{t}\overline{\mathrm{t}}} $ backgrounds in the three $ N_{\text{jet}} $ regions used in the global fit.
png pdf	Table 4: List of signal systematic uncertainties and their effects on the yields in the $ N_{\text{jet}}\ge $ 8 and $ N_{\mathrm{b}}\ge $ 4 bin for all three years combined. The signal model corresponds to $ m_{\mathrm{\widetilde{g}}}= $ 1800 GeV.
png pdf	Table 5: Background-only post-fit yields in the SR for all three data-taking years, with pre-fit signal yields. The uncertainty shown for total background corresponds to the post-fit uncertainty, while that for the signal is statistical only.

Summary

This analysis investigates the existence of physics beyond the standard model in events characterized by high multiplicities of jets and bottom quark (b) jets in the single-lepton final state, without a requirement on missing transverse momentum. The scalar sum of the large-radius jet masses ($ M_{\mathrm{J}} $) in an event is used for both background rejection and prediction. A simultaneous fit to the $ M_{\mathrm{J}} $ templates, in bins of jet multiplicity $ N_{\text{jet}} $ and the number of b-tagged jets $ N_{\mathrm{b}} $, is performed to extract potential excesses in data. The templates, derived from simulation, are corrected by measurements comparing data and simulation in dedicated control regions. This method enables a data-driven prediction of background across bins of $ N_{\text{jet}} $, $ N_{\mathrm{b}} $, and $ M_{\mathrm{J}} $. The observed event yields are consistent with the background predictions. The result is interpreted within the framework of $ R $-parity violating supersymmetry under the minimal flavor violating scenario. The search focuses on gluino pair production, where each gluino decays to a top, a bottom, and a strange quark via the $ \lambda^{\prime\prime}_{323} $ coupling. Using proton-proton collisions at $ \sqrt{s}= $ 13 TeV from the CERN LHC collected by the CMS experiment from 2016 to 2018 and corresponding to an integrated luminosity of 138 fb$ ^{-1} $, gluinos are excluded up to a mass of 1890 GeV at 95% confidence level. This result exceeds existing limits on the considered gluino pair production model.

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