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Comparison of the distribution of $\chi^2_{\mathrm{min}}$ from the kinematic fitter for data and the expectation from the background estimates for the combined electron and muon channels. The MC simulation is normalized to the expectation for the SM ($\Br(t\to H^+b)=0$). The uncertainty shown on the background estimate is the combination in quadrature of the $\pm 1 \sigma$~systematic uncertainties. The final bin also contains the overflow entries.

Comparison of the dijet mass distribution before (upper part) and after (lower part) the kinematic fit and the $\chi^2 < 10$ selection criterion. The distribution is shown for MC simulations of SM $\ttbar$~decays and the $m_{H^+} = 110$~GeV signal ($\ttbar\rightarrow H^+bW^-\bar{b}$). The curves are normalized to the same area.

Comparison of the dijet mass distribution before (upper part) and after (lower part) the kinematic fit and the $\chi^2 < 10$ selection criterion. The distribution is shown for MC simulations of SM $\ttbar$~decays and the $m_{H^+} = 110$~GeV signal ($\ttbar\rightarrow H^+bW^-\bar{b}$). The curves are normalized to the same area.

noimg: The expected numbers of events from SM processes, integrated over the full range of dijet masses and the observed number of events in the data after all the selection requirements. The expected number of events in the case of a signal with $m_{H^ +}=110$~GeV and $\Br(t\to H^+b)=10\%$~is also shown. The $\ttbar\rightarrow W^+b W^-\bar{b}$ numbers include both the lepton + jets and dilepton decay channels. The uncertainties are the sum of the contributions from statistics and systematic uncertainties.: Effect of the systematic uncertainties on the event rate of $\ttbar$~background and signal ($m_{H^+}=110$~GeV) events before any reduction from the likelihood fit, described in Sect.~\ref{results}.

The dijet mass distribution from data and the expectation from the SM ($\Br=0$). The error bars represent the statistical uncertainty on the data. The uncertainty shown on the background estimate is the combination in quadrature of the $\pm 1 \sigma$~systematic uncertainties, accounting for the constraint from the profile likelihood fit. The first and last bins contain the underflow and overflow events respectively.

The extracted 95\% CL upper limits on ${\mathcal B}(t \rightarrow H^+b$), assuming that $\Br(H^{+}\rightarrow\csbar) = 100\%$, are shown for a range of charged Higgs masses from 90 GeV to 150 GeV. The limits shown are calculated using the CL$_{\mathrm{s}}$ limit-setting procedure.