TOP-14-003

Search for anomalous single top quark production in association with a photon

Abstract

A search for single top quark production through flavor-changing neutral currents in the anomalous tqγ vertex is presented in proton-proton collisions at a center-of-mass energy of 8 TeV. The analysis is based on a data-set corresponding to an integrated luminosity of 19.1 fb−1 collected with the CMS detector. The search is performed on events with one isolated muon and jets in the final state. No evidence for a signal is observed. Upper limits on the strengths of the anomalous couplings at leading order for vertices involving a top quark, a photon, and another up-like quark are set at 95% confidence level to be $\kappa_{tu\gamma}$<0.028 and $\kappa_{tc\gamma}$<0.094. The corresponding upper bounds on the top quark decay branching ratios are $BR(t\rightarrow u+\gamma)$<0.0161% and $BR(t\rightarrow c+\gamma)$<0.182%.

Public Document

The document CMS-PAS-TOP-14-003 can be found on the CERN Document Server, here.

Control plots and BDT distributions

The BDT output distribution for data, all backgrounds, and tγu. The Wγ+jets and W+jets contributions are estimated from data. The tuγ signal sample are normalized to a cross section of 1 pb. The uncertainty band includes both the statistical and systematic uncertainties. The statistical part is the dominant contribution.

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The BDT output distribution for data, all backgrounds, and tγc. The Wγ+jets and W+jets contributions are estimated from data. The tcγ signal sample are normalized to a cross section of 1 pb.

The uncertainty band includes both the statistical and systematic uncertainties. The statistical part is the dominant contribution.

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Distributions of $p_{T}$ of the photon after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of η of the photon after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of muon $p_{T}$ after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of muon η after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of b-jet $p_{T}$ after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of b-jet η after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of $\Delta$R(μ, γ) after the final event selection and background estimations.

The uncertainty band includes both the statistical and systematic uncertainties. The statistical part is the dominant contribution.

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Distributions of $\Delta$ R(b − jet, γ) after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of cos(W, γ) after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of cos(top, γ) after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Distributions of jet multiplicity after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty

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Distributions of b-tagging discriminator after the final event selection and background estimations. The band includes both statistical and systematic uncertainties and it is dominated by the statistical uncertainty.

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Exclusion plots


The 95% C.L. upper limit on the $tu\gamma$ signal cross section as a function of $\kappa_{tu\gamma}$, as well as the predicted cross section calculated by Protos

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The 95% C.L. upper limit on the $tc\gamma$ signal cross section as a function of $\kappa_{tc\gamma}$, as well as the predicted cross section calculated by Protos

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Results


The observed and expected 95% exclusion limits on the signal cross section, anomalous couplings, and branching ratios with and without including the QCD higher order corrections on the signal cross section. PNG

Comparison plots


The observed 95% C.L. upper limit on the $BR(t\rightarrow u+\gamma)$ versus the strength of the anomalous coupling $\kappa_{tu\gamma}$ for the DELPHI, ZEUS, H1, CDF and CMS collaborations.

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The observed 95% C.L. upper limit on the $BR(t\rightarrow u+\gamma)$ versus $BR(t\rightarrow u+Z)$ for the DELPHI, ZEUS, H1, DŲ, CDF, ATLAS and CMS collaborations.

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Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf BR_BR.pdf r1 manage 14.9 K 2014-05-10 - 11:10 RezaGoldouzian tz tgamma comparison plots
PNGpng BR_BR.png r1 manage 21.1 K 2014-05-11 - 11:52 RezaGoldouzian tz tgamma comparison plots
PDFpdf CSV.pdf r1 manage 17.2 K 2014-05-10 - 10:04 RezaGoldouzian distribution of CSV discriminator
PNGpng CSV.png r1 manage 31.8 K 2014-05-11 - 10:41 RezaGoldouzian distribution of CSV discriminator
PDFpdf costopgamma.pdf r1 manage 18.8 K 2014-05-10 - 10:04 RezaGoldouzian distribution of cos(top,gamma)
PNGpng costopgamma.png r1 manage 35.2 K 2014-05-11 - 11:04 RezaGoldouzian distribution of cos(top,gamma)
PDFpdf deltarphotonjetpdf.pdf r1 manage 16.1 K 2014-05-10 - 10:06 RezaGoldouzian distribution of deltaR(gamma,bjet)
PNGpng deltarphotonjetpdf.png r1 manage 29.2 K 2014-05-11 - 11:05 RezaGoldouzian distribution of deltaR(gamma,bjet)
PDFpdf deltarphotonmuonpdf.pdf r1 manage 16.1 K 2014-05-10 - 10:07 RezaGoldouzian distribution of deltaR(gamma,muon)
PNGpng deltarphotonmuonpdf.png r1 manage 28.9 K 2014-05-11 - 11:05 RezaGoldouzian distribution of deltaR(gamma,muon)
PDFpdf etajetpdf.pdf r1 manage 16.7 K 2014-05-10 - 09:56 RezaGoldouzian distribution of b-jet eta
PNGpng etajetpdf.png r1 manage 28.2 K 2014-05-11 - 10:03 RezaGoldouzian distribution of b-jet eta
PDFpdf etamuonpdf.pdf r1 manage 16.5 K 2014-05-10 - 09:35 RezaGoldouzian distribution of b-jet eta
PNGpng etamuonpdf.png r1 manage 28.9 K 2014-05-11 - 10:03 RezaGoldouzian distribution of muon eta
PDFpdf jetmulti.pdf r1 manage 16.0 K 2014-05-10 - 10:07 RezaGoldouzian jet multiplicity
PNGpng jetmulti.png r1 manage 29.4 K 2014-05-11 - 11:06 RezaGoldouzian jet multiplicity
PDFpdf kappa_BR.pdf r1 manage 15.0 K 2014-05-10 - 11:11 RezaGoldouzian kappa BR comparison plots
PNGpng kappa_BR.png r1 manage 18.5 K 2014-05-11 - 11:52 RezaGoldouzian kappa BR comparison plots
PNGpng limitResults.png r1 manage 63.2 K 2014-05-10 - 19:30 RezaGoldouzian upper limit results
PDFpdf newcoswgamma.pdf r1 manage 18.7 K 2014-05-10 - 10:03 RezaGoldouzian distribution of cos(W,gamma)
PNGpng newcoswgamma.png r1 manage 34.3 K 2014-05-11 - 11:07 RezaGoldouzian distribution of cos(W,gamma)
PDFpdf newetaphpton.pdf r1 manage 16.6 K 2014-05-10 - 09:29 RezaGoldouzian distribution of photon eta
PNGpng newetaphpton.png r1 manage 29.0 K 2014-05-11 - 10:02 RezaGoldouzian distribution of photon eta
PDFpdf newptphoton.pdf r1 manage 17.7 K 2014-05-10 - 09:23 RezaGoldouzian distribution of photon Pt
PNGpng newptphoton.png r1 manage 30.6 K 2014-05-11 - 10:02 RezaGoldouzian distribution of photon Pt
PDFpdf ptjetpdf.pdf r1 manage 17.5 K 2014-05-10 - 09:37 RezaGoldouzian distribution of b-jet pt
PNGpng ptjetpdf.png r1 manage 32.3 K 2014-05-11 - 10:04 RezaGoldouzian distribution of b-jet pt
PDFpdf ptmuonpdf.pdf r1 manage 16.9 K 2014-05-10 - 09:38 RezaGoldouzian distribution of muon pt
PNGpng ptmuonpdf.png r1 manage 31.2 K 2014-05-11 - 10:04 RezaGoldouzian distribution of muon pt
PDFpdf tGclimit.pdf r1 manage 15.5 K 2014-05-10 - 10:47 RezaGoldouzian exclusion plot tgammac
PNGpng tGclimit.png r1 manage 29.3 K 2014-05-11 - 11:43 RezaGoldouzian exclusion plot tgammac
PDFpdf tGulimit.pdf r1 manage 15.4 K 2014-05-10 - 10:48 RezaGoldouzian exclusion plot tgammau
PNGpng tGulimit.png r1 manage 27.1 K 2014-05-11 - 11:44 RezaGoldouzian exclusion plot tgammau
PDFpdf tcgammaBDT.pdf r1 manage 17.9 K 2014-05-10 - 09:07 RezaGoldouzian BDT output fot tcgamma signal channel
PNGpng tcgammaBDT.png r1 manage 31.3 K 2014-05-11 - 11:37 RezaGoldouzian exclusion plot tgammac
PDFpdf tugammaBDT.pdf r1 manage 17.9 K 2014-05-10 - 09:02 RezaGoldouzian BDT output fot tugamma signal chanel
PNGpng tugammaBDT.png r1 manage 31.2 K 2014-05-11 - 11:37 RezaGoldouzian BDT output fot tugamma signal chanel
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Topic revision: r12 - 2014-05-14 - AndreasMeyer
 
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