TOP-12-040:
Observation of Associated Production of a Single Top Quark and W Boson in pp Collisions at $\sqrt{s}$ = 8 TeV

Abstract

The observation of the associated production of a single top quark and W boson in pp collisions at $\sqrt{s}$ = 8 TeV with the CMS experiment at the LHC is presented. The analyzed data corresponds to an integrated luminosity of 12.2 $fb^{-1}$. The measurement is performed using events with two leptons and a jet originated from a b quark. A multivariate analysis based on kinematic properties is utilized to separate the signal from the $t\bar{t}$ background. The signal is observed with a 6.0 standard deviation excess above a background only hypothesis. A production cross section of $23.4^{+5.5}_{-5.4}$ pb is measured, in agreement with the standard model expectation of $22.2\pm1.5$ pb.

Result

Observed Significance: $6.0 \sigma$

Expected Significance: $5.4^{+1.5}_{-1.4} \sigma$

Cross Section: $\sigma_{tW} = 23.4^{+5.5}_{-5.5}$

$|V_{tb}| = \sqrt{\frac{\sigma_{tW}}{\sigma^{th}_{tW}}} = 1.03 \pm 0.12 (exp.) \pm 0.04 (th.) $

Figures in PAS

Click on image for pdf version of figure.

Figure Caption
fgSTtWfirst.pdf fgSTtWfirst.pdf Figure 1 Leading order Feynman diagrams for single-top-quark production in the tW mode, the charge-conjugate modes are implicitly included.
Figure2_twglubox.pdf Figure2_twglufus.pdf Figure2_twqqbar.pdf Figure 2 Feynman diagrams for \tW single-top-quark production at next-to-leading order that are removed from the signal definition in the DR scheme, the charge-conjugate modes are implicitly included.
NlooseJet20_1j1t.pdf NlooseJet20_2j1t.pdf NlooseJet20_2j2t.pdf Figure 3 Distribution of number of loose jets in the 1j1t (left), 2j1t (center), and 2j2t (right) regions in data and simulation. Plots show a combination of all three decay channels after full event selection is applied.
ptsys_1j1t.pdf ptsys_2j1t.pdf ptsys_2j2t.pdf Figure 4 Distribution of $p_{\mathrm{T}}$ of the system in the 1j1t (left), 2j1t (center), and 2j2t (right) regions in data and simulation. Plots show a combination of all three decay channels after full event selection is applied.
BDT35_1j1t.pdf BDT35_2j1t.pdf BDT35_2j2t.pdf Figure 5 Distribution of BDT discriminant for data and simulation separated in the 1j1t signal region (left) and the 2j1t (center) and 2j2t (right) control regions.
BDT35_1j1t_emu.pdf BDT35_2j1t_emu.pdf BDT35_2j2t_emu.pdf Figure 6 Distribution of BDT discriminant for data and simulation separated in the 1j1t signal region (left) and the 2j1t (center) and 2j2t (right) control regions in the $e\mu$ channel.
BDT35_1j0t.pdf BDT35_2j0t.pdf Figure 7 Distribution of BDT discriminant for data and simulation separated in the 1j0t (left) and 2j0t (right) control regions.
regionPlot_all_fitted_uncert.pdf Figure 8 Event yields in data and simulation in the 1j1t signal region as well the 2j1t and 2j2t control regions for the cut-based analysis.

Tables in PAS

Table Caption
Table1.png Table 1 Variables used for BDT training
Table2.png Table 2 Systematic uncertainties extracted by fixing sources one at a time and measuring difference in cross section uncertainty.

Topic attachments
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PDFpdf BDT35_1j0t.pdf r2 r1 manage 25.1 K 2013-07-17 - 18:04 DannyNoonan  
PNGpng BDT35_1j0t.png r2 r1 manage 27.3 K 2013-07-17 - 18:04 DannyNoonan  
PDFpdf BDT35_1j1t.pdf r2 r1 manage 25.7 K 2013-07-17 - 16:47 DannyNoonan  
PNGpng BDT35_1j1t.png r2 r1 manage 27.6 K 2013-07-17 - 16:47 DannyNoonan  
PDFpdf BDT35_1j1t_emu.pdf r1 manage 26.6 K 2013-07-18 - 00:51 DannyNoonan  
PNGpng BDT35_1j1t_emu.png r1 manage 28.6 K 2013-07-18 - 00:51 DannyNoonan  
PDFpdf BDT35_2j0t.pdf r2 r1 manage 25.7 K 2013-07-17 - 18:04 DannyNoonan  
PNGpng BDT35_2j0t.png r2 r1 manage 28.1 K 2013-07-17 - 18:04 DannyNoonan  
PDFpdf BDT35_2j1t.pdf r2 r1 manage 24.6 K 2013-07-17 - 16:47 DannyNoonan  
PNGpng BDT35_2j1t.png r2 r1 manage 26.5 K 2013-07-17 - 16:47 DannyNoonan  
PDFpdf BDT35_2j1t_emu.pdf r1 manage 25.7 K 2013-07-18 - 00:51 DannyNoonan  
PNGpng BDT35_2j1t_emu.png r1 manage 26.9 K 2013-07-18 - 00:51 DannyNoonan  
PDFpdf BDT35_2j2t.pdf r2 r1 manage 26.0 K 2013-07-17 - 18:03 DannyNoonan  
PNGpng BDT35_2j2t.png r2 r1 manage 27.7 K 2013-07-17 - 18:03 DannyNoonan  
PDFpdf BDT35_2j2t_emu.pdf r1 manage 26.1 K 2013-07-18 - 00:51 DannyNoonan  
PNGpng BDT35_2j2t_emu.png r1 manage 26.7 K 2013-07-18 - 00:51 DannyNoonan  
PDFpdf Figure2_twglubox.pdf r1 manage 16.0 K 2013-07-15 - 23:14 DannyNoonan  
PNGpng Figure2_twglubox.png r1 manage 4.8 K 2013-07-15 - 23:22 DannyNoonan  
PDFpdf Figure2_twglufus.pdf r1 manage 16.1 K 2013-07-15 - 23:14 DannyNoonan  
PNGpng Figure2_twglufus.png r1 manage 5.1 K 2013-07-15 - 23:22 DannyNoonan  
PDFpdf Figure2_twqqbar.pdf r1 manage 15.7 K 2013-07-15 - 23:14 DannyNoonan  
PNGpng Figure2_twqqbar.png r1 manage 4.6 K 2013-07-15 - 23:46 DannyNoonan  
PDFpdf NlooseJet20_1j1t.pdf r1 manage 19.2 K 2013-07-17 - 16:45 DannyNoonan  
PNGpng NlooseJet20_1j1t.png r3 r2 r1 manage 21.5 K 2013-07-17 - 18:00 DannyNoonan  
PDFpdf NlooseJet20_2j1t.pdf r2 r1 manage 19.3 K 2013-07-17 - 18:00 DannyNoonan  
PNGpng NlooseJet20_2j1t.png r3 r2 r1 manage 22.2 K 2013-07-17 - 18:00 DannyNoonan  
PDFpdf NlooseJet20_2j2t.pdf r2 r1 manage 18.9 K 2013-07-17 - 18:00 DannyNoonan  
PNGpng NlooseJet20_2j2t.png r3 r2 r1 manage 21.0 K 2013-07-17 - 18:00 DannyNoonan  
PNGpng Table1.png r1 manage 44.9 K 2013-07-15 - 23:46 DannyNoonan  
PNGpng Table2.png r1 manage 53.2 K 2013-07-15 - 23:46 DannyNoonan  
PNGpng crossSection.png r1 manage 2.6 K 2013-07-18 - 04:25 DannyNoonan  
PNGpng expectedSig.png r1 manage 1.8 K 2013-07-18 - 04:25 DannyNoonan  
PDFpdf fgSTtWfirst.pdf r1 manage 6.6 K 2013-07-15 - 23:14 DannyNoonan  
PNGpng fgSTtWfirst.png r1 manage 2.7 K 2013-07-15 - 23:22 DannyNoonan  
PDFpdf fgSTtWsecond.pdf r1 manage 6.4 K 2013-07-15 - 23:14 DannyNoonan  
PNGpng fgSTtWsecond.png r1 manage 2.8 K 2013-07-15 - 23:22 DannyNoonan  
PDFpdf ptsys_1j1t.pdf r2 r1 manage 29.6 K 2013-07-17 - 18:01 DannyNoonan  
PNGpng ptsys_1j1t.png r3 r2 r1 manage 29.3 K 2013-07-17 - 18:01 DannyNoonan  
PDFpdf ptsys_2j1t.pdf r2 r1 manage 29.7 K 2013-07-17 - 18:01 DannyNoonan  
PNGpng ptsys_2j1t.png r3 r2 r1 manage 29.4 K 2013-07-17 - 18:01 DannyNoonan  
PDFpdf ptsys_2j2t.pdf r2 r1 manage 29.4 K 2013-07-17 - 18:01 DannyNoonan  
PNGpng ptsys_2j2t.png r3 r2 r1 manage 28.2 K 2013-07-17 - 18:01 DannyNoonan  
PDFpdf regionPlot_all_fitted_uncert.pdf r2 r1 manage 15.1 K 2013-07-18 - 00:44 DannyNoonan  
PNGpng regionPlot_all_fitted_uncert.png r2 r1 manage 24.7 K 2013-07-18 - 00:44 DannyNoonan  
PNGpng vtb.png r1 manage 9.4 K 2013-07-18 - 04:25 DannyNoonan  
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Topic revision: r9 - 2013-07-18 - DannyNoonan
 
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