Responsible: ChristianContreras

Search for Vector-Like b′ Pair Production with Multilepton Final States in pp collisions at $\sqrt{s}$ = 8 TeV (B2G-13-003)

Further information

This analysis is documented in CMS-PAS-B2G-13-003. The Table and Figure numbers in the Material in PAS section correspond to the table and figure numbers in the PAS.

Abstract

A search for pair-production of vector-like partners of the b quark, b', is carried out in events with at least three leptons using 19.5fb$^{-1}$ of of integrated luminosity in pp collisions at $\sqrt{s}$ =8 TeV collected by the CMS experiment at the LHC. The data are binned in multiple exclusive channels according to the amount of expected standard model background in order to increase the search sensitivity. The observations are consistent with the standard model expectations. The search is interpreted for different b' masses and for varying branching ratios to the bZ, tW, and bH states. We exclude b' quarks with masses less than values in the range of 520$-$785 GeV (depending on the values of the branching ratios) at the 95% confidence level.

Approved tables and plots (click on plot to get larger version)

Material in PAS

Figures

Figure Caption
L4DY2Tau0b1_bprime750bZbZ_ST.png Figure 1: Background breakdown vs $S_\text{T}$ require 4 Leptons, OSSF2, on-Z, Tau0, 1 b-jet. For b$^\prime$b$^\prime$ $\rightarrow \textrm{bZ}\textrm{bZ}$ as the signal with b$^\prime$ having a mass of 750 GeV.
L4DY2Tau0b1_bprime750tWtW_ST.png Figure 2: Background breakdown vs $S_\text{T}$ require 4 Leptons, OSSF2, on-Z, Tau0, 1 b-jet. For b$^\prime$b$^\prime$ $\rightarrow \textrm{tW}\textrm{tW}$ as the signal with b$^\prime$ having a mass of 750 GeV.
L3DY1ZVZHTau0b1_bprime750bZbZ_ST.png Figure 3: Background breakdown vs $S_\text{T}$ require 3 Leptons, OSSF1, above-Z, Tau0, 1 b-jet. For b$^\prime$b$^\prime$ $\rightarrow \textrm{bZ}\textrm{bZ}$ as the signal with b$^\prime$ having a mass of 750 GeV.
L3DY1ZVZHTau0b1_bprime750tWtW_ST.png Figure 4: Background breakdown vs $S_\text{T}$ require 3 Leptons, OSSF1, above-Z, Tau0, 1 b-jet. For b$^\prime$b$^\prime$ $\rightarrow \textrm{tW}\textrm{tW}$ as the signal with b$^\prime$ having a mass of 750 GeV.
bZbZ_exclusion_limits_withRPV_1D.png Figure 5: Cross section times branching ratio exclusion curves for a b$^\prime$ as a function of its mass for the decay modes b$^\prime$b$^\prime$ $\rightarrow \textrm{bZ}\textrm{bZ}$. The figure show expected (dashed), observed (solid) exclusions; sigma bands correspond to the experimental uncertainties.
tWtW_exclusion_limits_withRPV_1D.png Figure 6: Cross section times branching ratio exclusion curves for a b$^\prime$ as a function of its mass for the decay modes b$^\prime$b$^\prime$ $\rightarrow \textrm{tW}\textrm{tW}$. The figure show expected (dashed), observed (solid) exclusions; sigma bands correspond to the experimental uncertainties.
bHbH_exclusion_limits_withRPV_1D.png Figure 7: Cross section times branching ratio exclusion curves for a b$^\prime$ as a function of its mass for the decay modes b$^\prime$b$^\prime$ $\rightarrow \textrm{bH}\textrm{bH}$. The figure show expected (dashed), observed (solid) exclusions; sigma bands correspond to the experimental uncertainties.
bZtW_exclusion_limits_withRPV_2D.png Figure 8: Exclusion limits for pair-produced b$^\prime$ quarks going to multileptons in the two-dimensional plane of branching ratio of b$^\prime$ to $\textrm{bZ}$ vs. b$^\prime$ mass. Signal points to the left of the curve are excluded. The y = 0 axis corresponds to b$^\prime$b$^\prime$ $\rightarrow \textrm{tW}\textrm{tW}$ and the $y = 1$ axis to b$^\prime$b$^\prime$ $\rightarrow \textrm{bZ}\textrm{bZ}$. The branching ratio for b$^\prime$ $\rightarrow \textrm{bH}$ is set to zero. We apply a conservative 10% theory uncertainty.
B2G-3-003_exclusion_bH25pct_reweighted.png Figure 9: Observed and expected 95% confidence level upper limits for the b$^\prime$ quark production cross section for branching ratio into into $\textrm{tW}$, $\textrm{bH}$, and $\textrm{bZ}$ of 50%, 25%, and 25%, respectively.
rainbowPlot_exp_v6.png Figure 10: Expected exclusion curves as a function of branching ratios. The $\mathcal{B}(\textrm{b'}\rightarrow \textrm{bZ})$ is plotted as a function of the b$^\prime$ mass and the various curves represent fixed $\mathcal{B}(\textrm{b'}\rightarrow \textrm{bH})$ from 0.0 (the rightmost) to 1.0 ( the leftmost)
rainbowPlot_obs_v3.png Figure 11: Observed exclusion curves as a function of branching ratios. The $\mathcal{B}(\textrm{b'}\rightarrow \textrm{bZ})$ is plotted as a function of the b$^\prime$ mass and the various curves represent fixed $\mathcal{B}(\textrm{b'}\rightarrow \textrm{bH})$ from 0.0 (the rightmost) to 1.0 ( the leftmost)
triangle_exp_exlusion_limit_v0.png Figure 12: Expected limit results with varied branching ratio of $\textrm{tW}$, $\textrm{bH}$, and $\textrm{bZ}$ in steps of 0.1.
triangle_obs_exlusion_limit_v0.png Figure 13: Observed limit results with varied branching ratio of $\textrm{tW}$, $\textrm{bH}$, and $\textrm{bZ}$ in steps of 0.1.

Tables

Table Caption
SystematicTable.png Table 1: The systematic uncertainties associated with this analysis.
ResultsTable4Lepton.png Table 2: Observed yields for four lepton events from 19.5fb$^{-1}$ recorded in 2012. The channels are broken down by the number of and mass of any opposite-sign same-flavor pairs (whether on or off Z), whether the leptons include taus, whether there are any b jets present and the $S_{\rm T}$. Expected yields are the sum of simulation and data-driven estimates of backgrounds in each channel. The channels are exclusive. Channels marked with an asterisk are used as control regions and are excluded from the limit calculations. Also, those channels with a dagger mark are used in the limit setting procedure and are representative of the top most sensitive channels for the $\textrm{b}^\prime$ decay with mass of 500 GeV where $\mathcal{B}(\textrm{b'}\rightarrow \textrm{bH})=1.0$.
ResultsTable3Lepton.png Table 3: Observed yields for three lepton events. The channels are broken down by the number of and mass of any opposite-sign, same-flavor pairs (whether on or off $\textrm{Z}$), whether the leptons include taus, whether there are any b jets present and the $S_{\rm T}$. Expected yields are the sum of simulation and data-driven estimates of backgrounds in each channel. The channels are exclusive. Channels marked with an asterisk are used as control regions and are excluded from the limit calculations. Also, those channels marked with a dagger are a representative subset of the top most sensitive channels for the $\textrm{b}^\prime$ decay, with a mass of 500 GeV and $\mathcal{B}(\textrm{b'}\rightarrow \textrm{bH})=1.0$, which are used in the limit setting procedure.
TriangleResultsTable.png Table 4: Sets of branching ratio values and the observed and expected 95% CL upper limits for the combined electron and muon channels.

Additional Material for B2G-13-003

Figure Caption
L3DY1ZVZLTau0b1_bprime750bHbH_ST.png Figure 1: Background breakdown vs $S_\text{T}$ require 3 Leptons, OSSF1, below-Z, Tau0, 1 b-jet. For b$^\prime$b$^\prime$ $\rightarrow \textrm{bHbH}$ as the signal with b$^\prime$ having a mass of 750 GeV.
L4DY1Tau1b0_bprime750bHbH_ST.png Figure 2: Background breakdown vs $S_\text{T}$ require 4 Leptons, OSSF1, on-Z, Tau1, no b-jet. For b$^\prime$b$^\prime$ $\rightarrow \textrm{bHbH}$ as the signal with b$^\prime$ having a mass of 750 GeV.
TTbarControl_SingleMu_RelIso_electronNonPrompt_CMS_Preliminary.png Figure 3: The isolation distribution of muons with large impact parameter ($\textrm{d$_{xy}$} > 0.02$ cm, primarily from jets) in a data sample enriched in $\textrm{t}\bar{\textrm{t}}$ $\rightarrow l\nu \textrm{bbjj}$.
TTbarControl_SingleMu_RelIso_CMS_Preliminary.png Figure 4: The isolation distribution of electrons with large impact parameter ($\textrm{d$_{xy}$} > 0.02$ cm, primarily from jets) in a data sample enriched in $\textrm{t}\bar{\textrm{t}}$ $\rightarrow l\nu \textrm{bbjj}$.

Additional Material from SUS-13-002 and SUS-13-003 (Links to Public Results)

Figure Caption
TTbar_ST_controlPlot.png Figure 1: The $S_\text{T}$ distribution in an opposite sign e$\textrm{$\mu$}$ $\textrm{t}\bar{\textrm{t}}$ control region. The uncertainties in the ratio plot below include both statistical and systematic uncertainties.
TTbarControl_DiLepton_HT_CMS_Preliminary.png Figure 2: Distribution for H$_{\text{T}}$ in the opposite sign e$\textrm{$\mu$}$ dilepton $\textrm{t}\bar{\textrm{t}}$ control region.
TTbarControl_DiLepton_MET_CMS_Preliminary.png Figure 3: Distributions for E$^{miss}_{\text{T}}$ in the opposite sign e$\textrm{$\mu$}$ dilepton $\textrm{t}\bar{\textrm{t}}$ control region.
WZControl_DiLepton_MT_CMS_Preliminary.png Figure 4: The transverse mass M$_\text{T}$ distribution of events in a data sample enriched in $\textrm{WZ}$ requiring an OSSF pair with $m(\ell\ell)$ in the Z-window and 50 GeV < E$^{miss}_{\text{T}}$ < 100 GeV.
WZControl_DiLepton_MET_CMS_Preliminary.png Figure 5: Distributions for E$^{miss}_{\text{T}}$ in the WZ control region.
mass_dist_met0to50GeVL4onZMass_PFMETvsAllMass.png Figure 6: 4-lepton mass distribution for low-E$^{miss}_{\text{T}}$, low-H$_{\text{T}}$ ZZ control region.
fsr_mu3_invmass_19p5ifb.png Figure 7: 3-muon invariant mass showing asymmetric internal photon conversion.
EffRatvsRdxy_leptons_CMS_Preliminary.png Figure 8: Efficiency ratio vs Rd$_{\textrm{xy}}$ ("b-ness of events") for muons and electrons.
FTvsFSB_DiLepton_highPt_CMS_Preliminary.png Figure 9: f$_\textrm{t}$-f$_\textrm{sb}$ for taus with p$_{\textrm{T}}$ between 40 and 60 GeV (f$_\textrm{t}$ is the fake-rate for taus and f$_\textrm{sb}$ is inversely proportional to jet activity).
FTvsFSB_DiLepton_lowPt_CMS_Preliminary.png Figure 10: f$_\textrm{t}$-f$_\textrm{sb}$ for taus with p$_{\textrm{T}}$ between 20 and 40 GeV (f$_\textrm{t}$ is the fake-rate for taus and f$_\textrm{sb}$ is inversely proportional to jet activity).
Topic attachments
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PDFpdf B2G-3-003_exclusion_bH25pct_reweighted.pdf r1 manage 14.6 K 2013-11-19 - 18:26 ChristianContreras  
PNGpng B2G-3-003_exclusion_bH25pct_reweighted.png r1 manage 149.2 K 2013-11-19 - 18:27 ChristianContreras  
PNGpng EffRatvsRdxy_leptons_CMS_Preliminary.png r1 manage 207.5 K 2013-11-20 - 18:24 ChristianContreras  
PNGpng FTvsFSB_DiLepton_highPt_CMS_Preliminary.png r1 manage 204.0 K 2013-11-20 - 18:24 ChristianContreras  
PNGpng FTvsFSB_DiLepton_lowPt_CMS_Preliminary.png r1 manage 204.3 K 2013-11-20 - 18:24 ChristianContreras  
PDFpdf L3DY1ZVZHTau0b1_bprime750bZbZ_ST.pdf r1 manage 15.4 K 2013-11-20 - 00:30 ChristianContreras  
PNGpng L3DY1ZVZHTau0b1_bprime750bZbZ_ST.png r1 manage 52.3 K 2013-11-20 - 00:27 ChristianContreras  
PDFpdf L3DY1ZVZHTau0b1_bprime750tWtW_ST.pdf r1 manage 15.4 K 2013-11-19 - 19:23 ChristianContreras  
PNGpng L3DY1ZVZHTau0b1_bprime750tWtW_ST.png r1 manage 52.9 K 2013-11-19 - 19:23 ChristianContreras  
PDFpdf L3DY1ZVZLTau0b1_bprime750bHbH_ST.pdf r1 manage 15.4 K 2013-11-22 - 02:05 ChristianContreras  
PNGpng L3DY1ZVZLTau0b1_bprime750bHbH_ST.png r1 manage 206.0 K 2013-11-22 - 02:22 ChristianContreras  
PDFpdf L4DY1Tau1b0_bprime750bHbH_ST.pdf r1 manage 15.3 K 2013-11-22 - 02:05 ChristianContreras  
PNGpng L4DY1Tau1b0_bprime750bHbH_ST.png r1 manage 203.4 K 2013-11-22 - 02:16 ChristianContreras  
PDFpdf L4DY2Tau0b1_bprime750bZbZ_ST.pdf r1 manage 15.0 K 2013-11-20 - 00:25 ChristianContreras  
PNGpng L4DY2Tau0b1_bprime750bZbZ_ST.png r1 manage 51.5 K 2013-11-20 - 00:26 ChristianContreras  
PDFpdf L4DY2Tau0b1_bprime750tWtW_ST.pdf r1 manage 15.0 K 2013-11-19 - 18:54 ChristianContreras  
PNGpng L4DY2Tau0b1_bprime750tWtW_ST.png r1 manage 51.8 K 2013-11-19 - 18:54 ChristianContreras  
PDFpdf ResultsTable3Lepton.pdf r1 manage 59.5 K 2013-11-19 - 22:39 ChristianContreras  
PNGpng ResultsTable3Lepton.png r2 r1 manage 250.0 K 2013-11-20 - 01:49 ChristianContreras  
PDFpdf ResultsTable4Lepton.pdf r1 manage 138.4 K 2013-11-19 - 22:39 ChristianContreras  
PNGpng ResultsTable4Lepton.png r2 r1 manage 260.4 K 2013-11-20 - 01:49 ChristianContreras  
PDFpdf SystematicTable.pdf r1 manage 68.0 K 2013-11-20 - 02:30 ChristianContreras  
PNGpng SystematicTable.png r1 manage 192.4 K 2013-11-20 - 02:30 ChristianContreras  
PNGpng TTbarControl_DiLepton_HT_CMS_Preliminary.png r1 manage 303.0 K 2013-11-20 - 18:06 ChristianContreras  
PNGpng TTbarControl_DiLepton_MET_CMS_Preliminary.png r1 manage 293.8 K 2013-11-20 - 18:06 ChristianContreras  
PDFpdf TTbarControl_SingleMu_RelIso_CMS_Preliminary.pdf r1 manage 15.0 K 2013-11-20 - 18:41 ChristianContreras  
PNGpng TTbarControl_SingleMu_RelIso_CMS_Preliminary.png r1 manage 173.9 K 2013-11-20 - 18:07 ChristianContreras  
PDFpdf TTbarControl_SingleMu_RelIso_electronNonPrompt_CMS_Preliminary.pdf r1 manage 14.8 K 2013-11-20 - 18:41 ChristianContreras  
PNGpng TTbarControl_SingleMu_RelIso_electronNonPrompt_CMS_Preliminary.png r1 manage 168.2 K 2013-11-20 - 18:06 ChristianContreras  
PNGpng TTbar_ST_controlPlot.png r1 manage 307.3 K 2013-11-21 - 17:43 ChristianContreras  
PDFpdf TriangleResultsTable.pdf r1 manage 45.1 K 2013-11-19 - 23:07 ChristianContreras  
PNGpng TriangleResultsTable.png r2 r1 manage 302.3 K 2013-11-20 - 01:53 ChristianContreras  
PNGpng WZControl_DiLepton_MET_CMS_Preliminary.png r1 manage 285.2 K 2013-11-20 - 18:06 ChristianContreras  
PNGpng WZControl_DiLepton_MT_CMS_Preliminary.png r1 manage 132.0 K 2013-11-22 - 03:36 ChristianContreras  
PDFpdf bHbH_exclusion_limits_withRPV_1D.pdf r1 manage 14.6 K 2013-11-19 - 18:02 ChristianContreras  
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PDFpdf bZbZ_exclusion_limits_withRPV_1D.pdf r1 manage 14.6 K 2013-11-18 - 23:16 ChristianContreras  
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PNGpng bZtW_exclusion_limits_withRPV_2D.png r1 manage 106.7 K 2013-11-19 - 18:21 ChristianContreras  
PNGpng fsr_mu3_invmass_19p5ifb.png r1 manage 194.3 K 2013-11-20 - 20:33 ChristianContreras  
PNGpng mass_dist_met0to50GeVL4onZMass_PFMETvsAllMass.png r1 manage 284.8 K 2013-11-20 - 18:06 ChristianContreras  
PDFpdf rainbowPlot_exp_v6.pdf r1 manage 24.3 K 2013-11-19 - 18:29 ChristianContreras  
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PDFpdf tWtW_exclusion_limits_withRPV_1D.pdf r1 manage 14.6 K 2013-11-19 - 17:59 ChristianContreras  
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