TOP-12-020 Measurement of W-helicity fractions in single top events topology

Abstract

We present a measurement of the W-boson helicity fractions in single-top events topology in muon+jets final state using LHC pp collisions at 7 TeV and 8 TeV center-of-mass energies. The datasets are collected by the CMS detector during 2011 (A) and 2012 (A+B) runs, respectively corresponding to an integrated luminosity of 1.14 /fb and 5.3 /fb. The combination of the two measurements yields FL = 0.293 0.069(stat.) 0.030(syst.), F0 = 0.713 0.114(stat.) 0.023(syst.) and FR = −0.006 0.057(stat.) 0.027(syst.). The measured polarizations are used to set limits on tWb anomalous couplings.

Public Document

The document CMS-PAS-TOP-12-020 can be found here.

Tables

Tables Caption
TOC.png Table 1: Event yields for data and simulation. The expected number of events are normalized to the integrated luminosities of 1.14 fb-1 and 5.3 fb-1 for 7 TeV and 8 TeV, respectively. Corrections from different sources are considered in simulation yields.
Tsyst2.png Table 2: Summary of systematics for individual analyses.
combSyst.png Table 3: Summary of systematics in combined likelihood.

Figures

Single-top production at Leading Order

tchannel22.png tchannel23.png

The kinematic distributions for the reconstructed top quark

Figure Caption
(a) mtopSevenII.png (b) mtopEightII.png
(c) newDef_cosThetaII.png (d) costhetaII.png
Figure 2: The reconstructed top quark mass (a, b) and the distribution of reconstructed cos(θ*l) (c, d) for data and simulation at 7 TeV (a, c) and 8 TeV (b, d) center-of-mass energies. Corrections from different sources are considered in simulation. The shape and normalization for QCD multi-jets and at sqrt(s) = 8 TeV for W+jets events are obtained from data. Link to pdf version for (a), (b), (c) and (d).
(a) eta-fwDjetsII.png (b) fwdjetetaII.png
(c) costhetaEtaSII.png (d) EtaFwDCosthetaEII.png
Figure 3: The pseudo-rapidity of the most forward jet in the event (a, b) and the distribution of reconstructed cos(θ*l) after the cut of fabs(η(fwd)) > 1.5 (c, d) for data and simulation at 7 TeV (a, c) and 8 TeV (b, d) center-of-mass energies. Corrections from different sources are considered in simulation. The shape and normalization for QCD multi-jets and at sqrt(s) = 8 TeV for W+jets events are obtained from data. Link to pdf version for (a), (b), (c) and (d).

Results from 7 TeV and 8 TeV combination

Figure Caption
(a) GL2DPAS.png (b) FinalFr.png Figure 4: Combined results from 8 TeV and 7 TeV center-of-mass energies for the W-helicity fractions in single-top event topology. Within the uncertainties, results are consistent with the SM predictions and the results from other measurements. Link to pdf version for (a) and (b).
The theory band in Figure 4b is updated with respect to the PAS note.
GLPlot.png Figure 5: Exclusion limits on real gL and gR anomalous couplings using the combined W-helicity measurement in single-top event topology. Link to pdf version.
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf EtaFwDCosthetaEII.pdf r1 manage 20.3 K 2013-03-06 - 11:26 AbidehJafari  
PNGpng EtaFwDCosthetaEII.png r1 manage 60.7 K 2013-03-06 - 11:26 AbidehJafari  
PDFpdf FinalFr.pdf r1 manage 14.6 K 2013-03-16 - 10:45 AbidehJafari  
PNGpng FinalFr.png r1 manage 18.2 K 2013-03-16 - 10:45 AbidehJafari  
PDFpdf FrPASGLII.pdf r1 manage 14.6 K 2013-03-06 - 12:11 AbidehJafari  
PNGpng FrPASGLII.png r1 manage 68.1 K 2013-03-06 - 12:11 AbidehJafari  
PDFpdf GL2DPAS.pdf r1 manage 15.5 K 2013-03-06 - 12:11 AbidehJafari  
PNGpng GL2DPAS.png r1 manage 49.9 K 2013-03-06 - 12:11 AbidehJafari  
PDFpdf GLPlot.pdf r1 manage 160.5 K 2013-03-06 - 12:11 AbidehJafari  
PNGpng GLPlot.png r1 manage 104.8 K 2013-03-06 - 12:11 AbidehJafari  
PNGpng TOC.png r1 manage 44.6 K 2013-03-06 - 10:47 AbidehJafari  
PNGpng Tsyst2.png r1 manage 80.1 K 2013-03-06 - 11:08 AbidehJafari  
PNGpng combSyst.png r1 manage 51.1 K 2013-03-06 - 11:13 AbidehJafari  
PDFpdf costhetaEtaSII.pdf r1 manage 16.8 K 2013-03-06 - 11:26 AbidehJafari  
PNGpng costhetaEtaSII.png r1 manage 56.7 K 2013-03-06 - 11:26 AbidehJafari  
PDFpdf costhetaII.pdf r1 manage 20.2 K 2013-03-06 - 11:26 AbidehJafari  
PNGpng costhetaII.png r1 manage 62.1 K 2013-03-06 - 11:26 AbidehJafari  
PDFpdf eta-fwDjetsII.pdf r1 manage 19.6 K 2013-03-06 - 11:26 AbidehJafari  
PNGpng eta-fwDjetsII.png r1 manage 59.6 K 2013-03-06 - 11:50 AbidehJafari  
PDFpdf fwdjetetaII.pdf r1 manage 19.5 K 2013-03-06 - 11:26 AbidehJafari  
PNGpng fwdjetetaII.png r1 manage 56.8 K 2013-03-06 - 11:26 AbidehJafari  
PDFpdf mtopEightII.pdf r1 manage 21.6 K 2013-03-06 - 11:27 AbidehJafari  
PNGpng mtopEightII.png r1 manage 69.8 K 2013-03-06 - 11:27 AbidehJafari  
PDFpdf mtopSevenII.pdf r1 manage 21.1 K 2013-03-06 - 11:27 AbidehJafari  
PNGpng mtopSevenII.png r1 manage 64.7 K 2013-03-06 - 11:27 AbidehJafari  
PDFpdf newDef_cosThetaII.pdf r1 manage 16.9 K 2013-03-06 - 11:27 AbidehJafari  
PNGpng newDef_cosThetaII.png r1 manage 55.7 K 2013-03-06 - 11:27 AbidehJafari  
PDFpdf tchannel22.pdf r1 manage 7.9 K 2013-03-06 - 12:11 AbidehJafari  
PNGpng tchannel22.png r1 manage 10.6 K 2013-03-06 - 12:11 AbidehJafari  
PDFpdf tchannel23.pdf r1 manage 9.7 K 2013-03-06 - 12:11 AbidehJafari  
PNGpng tchannel23.png r1 manage 16.0 K 2013-03-06 - 12:11 AbidehJafari  
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Topic revision: r4 - 2013-03-16 - MartijnMulders
 
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