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Measurement of forward $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ production in $pp$ collisions at $\sqrt{s}=8$ TeV

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Abstract

The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 $ fb^{-1}$. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.

Figures and captions

Average of uGB response in different intervals of $m_{\rm jj}$ for $ W \!+\! b \overline b $ (black) and $ t \overline t $ (green). The vertical error bars represent the standard error of the uGB mean in each interval.

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Projections of the simultaneous 4D-fit results for the $\mu^+$ sample: a) the dijet mass; b) the uGB response; the $\mathrm{BDT}({b|c})$ of the c) leading and d) sub-leading jets.

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Projections of the simultaneous 4D-fit results for the $\mu^-$ sample: a) the dijet mass; b) the uGB response; the $\mathrm{BDT}({b|c})$ of the c) leading and d) sub-leading jets.

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Projections of the simultaneous 4D-fit results for the $e^+$ sample: a) the dijet mass; b) the uGB response; the $\mathrm{BDT}({b|c})$ of the c) leading and d) sub-leading jets.

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Projections of the simultaneous 4D-fit results for the $e^-$ sample: a) the dijet mass; b) the uGB response; the $\mathrm{BDT}({b|c})$ of the c) leading and d) sub-leading jets.

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Graphical representation of Table 2. The outer bars (light yellow) correspond to the total uncertainties of the measured cross-sections and the inner bars (dark yellow) correspond to the statistical uncertainties. Theoretical prediction is represented by the black markers and error bars, where inner and outer uncertainties represent the scale and the total errors respectively.

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Animated gif made out of all figures.

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Tables and captions

Simultaneous 4D-fit results for each of the four signal categories ($e$ and $\mu$, negative and positive). The normalisation factor $K$ and the fitted yields per sample are shown. The uncertainties quoted are statistical only.

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Observed and expected cross-sections in the fiducial region defined in Section 3. The first uncertainty on the expected cross-sections is related to the scale variation and the second is the total. The first uncertainty on the observed cross-sections is statistical and the second is systematic.

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Correlation matrix for the measured cross sections. The correlations are given in %.

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Supplementary Material [file]

Supplementary material full pdf

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This ZIP file contains supplemetary material for the publication LHCb-PAPER-2016-038. The files are: Supplementary.pdf : An overview of the extra figures *.pdf, *.png, *.eps : The figures in variuous formats

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Created on 09 December 2018.Citation count from INSPIRE on 18 December 2018.