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Search for Scalar-Charm Pair-Production with the ATLAS Detector in $pp$ Collisions at $\sqrt{s}=$ 8 TeV ATLAS-CONF-2014-063 14 November 0021
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| Main document (CDS record) | pdf from CDS | |
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| Abstract | ||
| The results of a dedicated search for pair production of scalar partners of charm quarks are reported. The search is based on an integrated luminosity of 20.3 ${\rm fb}^{-1}$ of $pp$ collisions at $\sqrt{s}=8$ TeV recorded with the ATLAS detector. The search is performed using events with large missing transverse momentum and at least two jets, where the two leading jets are each tagged as originating from $c$ quarks. Events containing isolated electrons or muons are vetoed. In an $R$-parity conserving minimal supersymmetric scenario in which a single scalar-charm state is kinematically accessible, and where it decays exclusively into a charm quark and a neutralino, 95% confidence-level upper limits are obtained in the $\tilde{c}-\tilde{\chi}_{1}^{0}$ mass plane such that, for neutralino masses below 200 GeV, scalar charm masses up to 490 GeV are excluded. | ||
| Figures | ||
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Figure 1a: Distributions of mCT (left) and mcc (right), and their corresponding SM predictions. SR selections (mCT>150 GeV for the mcc distribution) are applied, other than for the variable plotted. Arrows indicate the SR requirements on mCT and mcc. In the ratio plots, the grey band corresponds to the combined MC statistical and experimental systematic uncertainty. png (49kB), pdf (45kB) |
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Figure 1b: Distributions of mCT (left) and mcc (right), and their corresponding SM predictions. SR selections (mCT>150 GeV for the mcc distribution) are applied, other than for the variable plotted. Arrows indicate the SR requirements on mCT and mcc. In the ratio plots, the grey band corresponds to the combined MC statistical and experimental systematic uncertainty. png (51kB), pdf (48kB) |
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Figure 2: Exclusion limits at 95% C.L. in the c-χ01 mass plane (colour online). The observed (solid red line) and expected (dashed blue line) limits include all uncertainties except for the theoretical signal cross-section uncertainty (PDF and scale). The bands around the expected limits show ± 1 σ uncertainties. The dotted lines around the observed limits represent the results obtained when moving the nominal signal cross section up or down by ± 1 σ theoretical uncertainty. png (107kB), pdf (63kB) |
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| Tables | ||
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Table 1: Expected and observed number of events for an integrated luminosity of 20.3 fb-1 at qrts=8 TeV. Top, Z+jets and W+jets contributions are estimated using the fit described in the text. For comparison, the numbers obtained using MC simulations only are shown in parentheses. The row labelled as `Others' reports sub-dominant electro-weak backgrounds estimated from MC. The total uncertainties are also reported. png (26kB), pdf (47kB) |
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