CMS-SUS-14-006

CMS-SUS-14-006 ; CERN-EP-2016-103
Search for top squark pair production in compressed-mass-spectrum scenarios in proton-proton collisions at $\sqrt{s} =$ 8 TeV using the ${\alpha_\mathrm{T}}$ variable
CMS Collaboration
29 May 2016
Phys. Lett. B 767 (2017) 403
Abstract: An inclusive search is performed for supersymmetry in final states containing jets and an apparent imbalance in transverse momentum, $\vec{p}_{\mathrm{T}}^{\text{miss}}$ , due to the production of unobserved weakly interacting particles in pp collisions at a centre-of-mass energy of 8 TeV. The data, recorded with the CMS detector at the CERN LHC, correspond to an integrated luminosity of 18.5 fb $^{-1}$ . The dimensionless kinematic variable ${\alpha_\mathrm{T}}$ is used to discriminate between events with genuine $\vec{p}_{\mathrm{T}}^{\text{miss}}$ associated with unobserved particles and spurious values of $\vec{p}_{\mathrm{T}}^{\text{miss}}$ arising from jet energy mismeasurements. No excess of event yields above the expected standard model backgrounds is observed. The results are interpreted in terms of constraints on the parameter space of several simplified models of supersymmetry that assume the pair production of top squarks. The search provides sensitivity to a broad range of top squark ( $\tilde{ \mathrm{ t } }$ ) decay modes, including the two-body decay $\tilde{ \mathrm{ t } } \to \mathrm{ c } \tilde{\chi}^0_1$ , where c is a charm quark and $\tilde{\chi}^0_1$ is the lightest neutralino, as well as the four-body decay $\tilde{ \mathrm{ t } } \to \mathrm{ b } \mathrm{ f \bar{f}' } \tilde{\chi}^0_1$ , where b is a bottom quark and $\mathrm{f}$ and $\mathrm{ \bar{f} }'$ are fermions produced in the decay of an intermediate off-shell W boson. These modes dominate in scenarios in which the top squark and lightest neutralino are nearly degenerate in mass. For these modes, top squarks with masses as large as 260 and 225 GeV are excluded, respectively, for the two- and four-body decays.
Links: e-print arXiv:1605.08993 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; CADI line (restricted) ;

Figures & Tables	Summary	Additional Figures & Tables	References	CMS Publications

The result of the search, in .csv format, is available here.
An implementation of the calculation of the alphaT variable in C++ is available at this link: code.

Figures
png pdf	Figure 1: The ${\alpha _\mathrm {T}}$ distribution observed in data for event samples that are recorded with an inclusive set of trigger conditions and satisfy (left) the selection criteria that define the $\mu$ +jets control region or (right) the criteria that define the signal region, with the additional requirement ${H_\text {T}} >$ 375 GeV. Event yields observed in data (solid circles) and SM expectations determined from simulation (solid histograms) are shown. Contributions from single top quark, diboson, Drell-Yan, and ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ + gauge boson production are collectively labelled "Residual SM''. The final bin contains the overflow events. The lower panels show the ratios of the binned yields obtained from data and Monte Carlo (MC) simulation as a function of $\alpha _\text {T}$ . The statistical uncertainties in the SM expectations are represented by the hatched areas.
png pdf	Figure 1-a: The ${\alpha _\mathrm {T}}$ distribution observed in data for event samples that are recorded with an inclusive set of trigger conditions and satisfy the selection criteria that define the $\mu$ +jets control region. Event yields observed in data (solid circles) and SM expectations determined from simulation (solid histograms) are shown. Contributions from single top quark, diboson, Drell-Yan, and ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ + gauge boson production are collectively labelled "Residual SM''. The final bin contains the overflow events. The lower panel shows the ratios of the binned yields obtained from data and Monte Carlo (MC) simulation as a function of $\alpha _\text {T}$ . The statistical uncertainties in the SM expectations are represented by the hatched areas.
png pdf	Figure 1-b: The ${\alpha _\mathrm {T}}$ distribution observed in data for event samples that are recorded with an inclusive set of trigger conditions and satisfy the criteria that define the signal region, with the additional requirement ${H_\text {T}} >$ 375 GeV . Event yields observed in data (solid circles) and SM expectations determined from simulation (solid histograms) are shown. Contributions from single top quark, diboson, Drell-Yan, and ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ + gauge boson production are collectively labelled "Residual SM''. The final bin contains the overflow events. The lower panel shows the ratios of the binned yields obtained from data and Monte Carlo (MC) simulation as a function of $\alpha _\text {T}$ . The statistical uncertainties in the SM expectations are represented by the hatched areas.
png pdf	Figure 2: Ratio $(N_\text {obs} - N_\text {pred})/N_\text {pred}$ as a function of ${H_\text {T}}$ for different event categories and/or control regions for (upper) events with two or three jets, and (lower) events with four or more jets; "b tag'' refers to a reconstructed b quark candidate. Error bars represent statistical uncertainties only, while the grey shaded bands represent the ${N_{\text {jet}}}$ - and ${H_\text {T}}$ -dependent uncertainties assumed in the transfer factors, as determined from the procedure described in the text.
png pdf	Figure 2-a: Ratio $(N_\text {obs} - N_\text {pred})/N_\text {pred}$ as a function of ${H_\text {T}}$ for different event categories and/or control regions for events with two or three jets; "b tag'' refers to a reconstructed b quark candidate. Error bars represent statistical uncertainties only, while the grey shaded bands represent the ${N_{\text {jet}}}$ - and ${H_\text {T}}$ -dependent uncertainties assumed in the transfer factors, as determined from the procedure described in the text.
png pdf	Figure 2-b: Ratio $(N_\text {obs} - N_\text {pred})/N_\text {pred}$ as a function of ${H_\text {T}}$ for different event categories and/or control regions for events with four or more jets; "b tag'' refers to a reconstructed b quark candidate. Error bars represent statistical uncertainties only, while the grey shaded bands represent the ${N_{\text {jet}}}$ - and ${H_\text {T}}$ -dependent uncertainties assumed in the transfer factors, as determined from the procedure described in the text.
png pdf	Figure 3: Observed upper limits on the production cross section at 95% CL (indicated by the colour scale) as a function of the top squark and $\tilde{\chi}^0_1$ masses for (upper left) $\tilde{ \mathrm{ t } } \to \mathrm{ c } \tilde{\chi}^0_1$ , (upper right) $\tilde{ \mathrm{ t } } \to {\mathrm{ b } \mathrm{{f{\bar{f}'}}} }\tilde{\chi}^0_1$ , (middle left) $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{\chi}^{\pm}_1$ with $m_{\tilde{\chi}^{\pm}_1 } = 0.25m_{\tilde{ \mathrm{ t } } } + 0.75m_{\tilde{\chi}^0_1 }$ , (middle right) $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{\chi}^{\pm}_1$ with $m_{\tilde{\chi}^{\pm}_1 } = 0.75m_{\tilde{ \mathrm{ t } } } + 0.25m_{\tilde{\chi}^0_1 }$ , and (lower left) $\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1$ . The black solid thick curves indicate the observed exclusion assuming the NLO+NLL SUSY production cross sections; the thin black curves show corresponding ${\pm }1\sigma$ theoretical uncertainties. The red thick dashed curves indicate median expected exclusions and the thin dashed and dotted curves indicate, respectively, their ${\pm }1 \sigma$ and ${\pm }2\sigma$ experimental uncertainties. A summary of the observed (solid) and median expected (dotted) exclusion contours is presented (lower right). The grey dotted diagonal lines delimit the region for which $m_{\tilde{ \mathrm{ t } } } > m_{\tilde{\chi}^0_1 }$ .
png pdf	Figure 3-a: Observed upper limits on the production cross section at 95% CL (indicated by the colour scale) as a function of the top squark and $\tilde{\chi}^0_1$ masses for $\tilde{ \mathrm{ t } } \to \mathrm{ c } \tilde{\chi}^0_1$ . The black solid thick curves indicate the observed exclusion assuming the NLO+NLL SUSY production cross sections; the thin black curves show corresponding ${\pm }1\sigma$ theoretical uncertainties. The red thick dashed curves indicate median expected exclusions and the thin dashed and dotted curves indicate, respectively, their ${\pm }1 \sigma$ and ${\pm }2\sigma$ experimental uncertainties. The grey dotted diagonal line delimits the region for which $m_{\tilde{ \mathrm{ t } } } > m_{\tilde{\chi}^0_1 }$ .
png pdf	Figure 3-b: Observed upper limits on the production cross section at 95% CL (indicated by the colour scale) as a function of the top squark and $\tilde{\chi}^0_1$ masses for $\tilde{ \mathrm{ t } } \to {\mathrm{ b } \mathrm{{f{\bar{f}'}}} }\tilde{\chi}^0_1$ . The black solid thick curves indicate the observed exclusion assuming the NLO+NLL SUSY production cross sections; the thin black curves show corresponding ${\pm }1\sigma$ theoretical uncertainties. The red thick dashed curves indicate median expected exclusions and the thin dashed and dotted curves indicate, respectively, their ${\pm }1 \sigma$ and ${\pm }2\sigma$ experimental uncertainties. The grey dotted diagonal line delimits the region for which $m_{\tilde{ \mathrm{ t } } } > m_{\tilde{\chi}^0_1 }$ .
png pdf	Figure 3-c: Observed upper limits on the production cross section at 95% CL (indicated by the colour scale) as a function of the top squark and $\tilde{\chi}^0_1$ masses for $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{\chi}^{\pm}_1$ . The black solid thick curves indicate the observed exclusion assuming the NLO+NLL SUSY production cross sections; the thin black curves show corresponding ${\pm }1\sigma$ theoretical uncertainties. The red thick dashed curves indicate median expected exclusions and the thin dashed and dotted curves indicate, respectively, their ${\pm }1 \sigma$ and ${\pm }2\sigma$ experimental uncertainties. The grey dotted diagonal line delimits the region for which $m_{\tilde{ \mathrm{ t } } } > m_{\tilde{\chi}^0_1 }$ .
png pdf	Figure 3-d: Observed upper limits on the production cross section at 95% CL (indicated by the colour scale) as a function of the top squark and $\tilde{\chi}^0_1$ masses for $\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{\chi}^{\pm}_1$ . The black solid thick curves indicate the observed exclusion assuming the NLO+NLL SUSY production cross sections; the thin black curves show corresponding ${\pm }1\sigma$ theoretical uncertainties. The red thick dashed curves indicate median expected exclusions and the thin dashed and dotted curves indicate, respectively, their ${\pm }1 \sigma$ and ${\pm }2\sigma$ experimental uncertainties. The grey dotted diagonal line delimits the region for which $m_{\tilde{ \mathrm{ t } } } > m_{\tilde{\chi}^0_1 }$ .
png pdf	Figure 3-e: Observed upper limits on the production cross section at 95% CL (indicated by the colour scale) as a function of the top squark and $\tilde{\chi}^0_1$ masses for $\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1$ . The black solid thick curves indicate the observed exclusion assuming the NLO+NLL SUSY production cross sections; the thin black curves show corresponding ${\pm }1\sigma$ theoretical uncertainties. The red thick dashed curves indicate median expected exclusions and the thin dashed and dotted curves indicate, respectively, their ${\pm }1 \sigma$ and ${\pm }2\sigma$ experimental uncertainties. The grey dotted diagonal line delimits the region for which $m_{\tilde{ \mathrm{ t } } } > m_{\tilde{\chi}^0_1 }$ .
png pdf	Figure 3-f: A summary of the observed (solid) and median expected (dotted) exclusion contours is presented.

Tables
png pdf	Table 1: ${H_\text {T}}$ -dependent thresholds on the ${E_{\mathrm {T}}}$ values of jets and ${\alpha _\mathrm {T}}$ values.
png pdf	Table 2: Systematic uncertainties (%) in the transfer factors, in intervals of ${N_{\text {jet}}}$ and ${H_\text {T}}$ .
png pdf	Table 3: Observed event yields in data and the "a priori'' SM expectations determined from event counts in the data control samples and transfer factors from simulation, in bins of ${H_\text {T}}$ , and categorised according to ${N_{\text {jet}}}$ and ${N_{\mathrm{ b } }}$ . Also shown are the SM expectations (labelled "SM'') obtained from a combined fit to control and signal regions under the SM hypothesis. The quoted uncertainties include the statistical as well as systematic components. For each row that lists fewer than the full set of columns, the final entry represents values obtained for an open final ${H_\text {T}}$ bin.

Summary

An inclusive search for supersymmetry with the CMS detector is reported, based on data from pp collisions collected at

$\sqrt{s} =$ 8 TeV, corresponding to an integrated luminosity of 18.5

$\pm$ 0.5 fb

$^{-1}$ . The final states analysed contain two or more jets with large transverse energies and a significant imbalance in the event transverse momentum, as expected in the production and decay of massive squarks and gluinos. Dedicated triggers made it possible to extend the phase space covered in this search to values of

${H_\text{T}}$ and

${H_\mathrm{T}}^{\text{miss}}$ as low as 200 and 130 GeV, respectively. These regions of low

${H_\text{T}}$ and

${H_\mathrm{T}}^{\text{miss}}$ correspond to regions of phase space that are highly populated in models with low-mass squarks and nearly degenerate mass spectra. The signal region is binned according to

${H_\text{T}}$ , the number of reconstructed jets, and the number of jets identified as originating from b quarks. The sum of standard model backgrounds in each bin is estimated from a simultaneous binned likelihood fit to the event yields in the signal region and in

$\mu$ +jets,

$\mu\mu$ +jets, and

$\gamma$ +jets control samples. The observed yields in the signal region are found to be in agreement with the expected contributions from standard model processes.

Limits are determined in the mass parameter space of simplified models that assume the direct pair production of top squarks. A comprehensive study of top squark decay modes is performed and interpreted in the parameter space of the loop-induced two-body decays to the neutralino and one c quark (

$\tilde{ \mathrm{ t } } \to \mathrm{ c }\tilde{\chi}^0_1$ ); four-body decays to the neutralino, one b quark, and an off-shell W boson (

$\tilde{ \mathrm{ t } } \to {\mathrm{ b } \mathrm{ f \bar{f}' } } \tilde{\chi}^0_1$ ); decays to one b quark and the lightest chargino (

$\tilde{ \mathrm{ t } } \to \mathrm{ b } \tilde{\chi}^{\pm}_1$ ), followed by the decay of the chargino to the lightest neutralino and an (off-shell) W boson; and the decay to a top quark and neutralino (

$\tilde{ \mathrm{ t } } \to \mathrm{ t } \tilde{\chi}^0_1$ ). In the region

$m_{\tilde{ \mathrm{ t } }} - m_{\tilde{\chi}^0_1} < m_{\mathrm{ W }}$ , top squarks with masses as large as 260 and 225 GeV, and neutralino masses up to 240 and 215 GeV, are excluded, respectively, for the two- and four-body decay modes. For top squark decays to

$\mathrm{ b }\tilde{\chi}^{\pm}_1$ , top squark masses up to 400 GeV and neutralino masses up to 225 GeV are excluded, depending on the mass of the chargino. For top squarks decaying to a top quark and a neutralino, top squark masses up to 500 GeV and neutralino masses up to 105 GeV are excluded.

In summary, the analysis provides sensitivity across a large region of parameter space in the (

$m_{\tilde{ \mathrm{ t } }}, m_{\tilde{\chi}^0_1}$ ) plane, covering several relevant top squark decay modes. In particular, the application of low thresholds to maximise signal acceptance provides sensitivity to models with compressed mass spectra. For top squark decays to b

$\tilde{\chi}^{\pm}_1$ , where the W boson from the

$\tilde{\chi}^{\pm}_1$ decay is off-shell, the presented studies improve on existing limits. Mass exclusions are reported in previously unexplored regions of the

$(m_{\tilde{ \mathrm{ t } }}, m_{\tilde{\chi}^{\pm}_1}, m_{\tilde{\chi}^0_1})$ parameter space that satisfy 100 GeV

$< {\Delta m} < m_\mathrm{ t }$ , of up to

$m_{\tilde{ \mathrm{ t } }} =$ 325,

$m_{\tilde{\chi}^{\pm}_1} = 250$ , and

$m_{\tilde{\chi}^0_1} =$ 225 GeV. For the region

${\Delta m} < m_\mathrm{ W }$ , the search provides the strongest expected mass exclusions, up to

$m_{\tilde{ \mathrm{ t } }} =$ 325 GeV, for the two-body decay

$\tilde{ \mathrm{ t } } \to \mathrm{ c }\tilde{\chi}^0_1$ when 30 GeV

$< {\Delta m} < m_\mathrm{ W }$ .

Additional Figures
png pdf	Additional Figure 1: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 0. (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 1-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 0.
png pdf	Additional Figure 1-b: Candidate signal event yields observed in data (solid circles) and SM expectations from the fit including the signal region with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 0.
png pdf	Additional Figure 2: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 0. (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 2-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 0.
png pdf	Additional Figure 2-b: Candidate signal event yields observed in data (solid circles) and SM expectations from the fit including the signal region with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 0.
png pdf	Additional Figure 3: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 1. (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 3-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 1.
png pdf	Additional Figure 3-b: Candidate signal event yields observed in data (solid circles) and SM expectations from the fit including the signal region with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 1.
png pdf	Additional Figure 4: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} = 1$ . (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 4-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} = 1$ .
png pdf	Additional Figure 4-b: Candidate signal event yields observed in data (solid circles) and SM expectations from the fit including the signal region with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} = 1$ .
png pdf	Additional Figure 5: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 2. (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 5-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 2.
png pdf	Additional Figure 5-b: Candidate signal event yields observed in data (solid circles) and SM expectations from the fit including the signal region with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy 2 $\geq n_\text {jet} \geq$ 3 and $n_\text {b} =$ 2.
png pdf	Additional Figure 6: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 2. (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 6-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 2.
png pdf	Additional Figure 6-b: Candidate signal event yields observed in data (solid circles) and SM expectations from the fit including the signal region with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 2.
png pdf	Additional Figure 7: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 3. (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 7-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 3.
png pdf	Additional Figure 7-b: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} =$ 3.
png pdf	Additional Figure 8: Candidate signal event yields observed in data (solid circles) and SM expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} \geq$ 4. (a) SM a priori expectations. (b) SM expectations from the fit including the signal region.
png pdf	Additional Figure 8-a: Candidate signal event yields observed in data (solid circles) and SM a priori expectations with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} \geq$ 4.
png pdf	Additional Figure 8-b: Candidate signal event yields observed in data (solid circles) and SM expectations from the fit including the signal region with their associated uncertainties (solid lines with bands) in bins of $H_\text {T}$ for events that satisfy $n_\text {jet} \geq$ 4 and $n_\text {b} \geq$ 4.

Additional Tables
png pdf	Additional Table 1: Event categorisation, according to $n_\text {jet}$ and $n_\text {b}$ , and the $H_\text {T}$ binning scheme used by the search. For each row that lists fewer than the full set of columns, the final entry represents values obtained for an open final $H_\text {T}$ bin.
png pdf	Additional Table 2: Relative expected background contributions (%) in the signal region per ( $n_\text {jet}$ , $n_\text {b}$ ) event category per $H_\text {T}$ bin as determined from simulation. The individual contributions are shown for $\mathrm{ Z } \rightarrow \nu \bar{\nu}$ +jets, W+jets, and ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ . Contributions from the SM processes of single top quark, diboson, Drell-Yan, and ${\mathrm{ t } {}\mathrm{ \bar{t} } }$ +gauge boson (W, Z, H) production are collectively labelled "Residual SM''. QCD multijet production is considered to be negligible. For each row that lists fewer than the full set of columns, the final entry represents values obtained for an open final $H_\text {T}$ bin.
png pdf	Additional Table 3: Binned yields in the $\mu$ +jets control sample, for events categorised according to $n_\text {jet}$ , $n_\text {b}$ , and $H_\text {T}$ , and the corresponding SM expectations (labelled "SM'') as obtained from a combined fit to the control and signal regions under the background-only hypothesis. The quoted uncertainties include both statistical and systematic components. For each row that lists fewer than the full set of columns, the final entry represents values obtained for an open final $H_\text {T}$ bin.
png pdf	Additional Table 4: Binned yields in the $\mu \mu$ +jets control sample, for events categorised according to $n_\text {jet}$ , $n_\text {b}$ , and $H_\text {T}$ , and the corresponding SM expectations (labelled "SM'') as obtained from a combined fit to the control and signal regions under the background-only hypothesis. The quoted uncertainties include both statistical and systematic components. For each row that lists fewer than the full set of columns, the final entry represents values obtained for an open final $H_\text {T}$ bin.
png pdf	Additional Table 5: Binned yields in the $\gamma$ +jets control sample, for events categorised according to $n_\text {jet}$ , $n_\text {b}$ , and $H_\text {T}$ , and the corresponding SM expectations (labelled "SM'') as obtained from a combined fit to the control and signal regions under the background-only hypothesis. The quoted uncertainties include both statistical and systematic components. For each row that lists fewer than the full set of columns, the final entry represents values obtained for an open final $H_\text {T}$ bin.
png pdf	Additional Table 6: Cumulative signal acceptance times efficiency (%) for the event selection criteria that define the signal region, for models involving the pair production of top squarks and the following decay modes: a loop-induced, flavour-changing neutral current decay to a charm quark and a neutralino, $\tilde{ \mathrm{ t } } \to \mathrm{c} \tilde{\chi}^0_1$ , or a four-body decay, $\tilde{ \mathrm{ t } } \to \mathrm{ b }\mathrm{ f \bar{f}' } \tilde{\chi}^0_1$ , where b is a bottom quark with $\mathrm{f}$ and $\mathrm{\bar{f}'}$ fermions from, for example, an off-shell W boson decay. The models are defined by the masses (GeV) of the top squark and the neutralino, ( $m_{ \tilde{ \mathrm{ t } } }$ , $m_{\tilde{\chi}^0_1 }$ ).

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