Search for same-sign top-quark pair production at sqrt(s) = 7 TeV and limits on flavour changing neutral currents in the top sector

CMS Collaboration

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Search for same-sign top-quark pair production at sqrt(s) = 7 TeV and limits on flavour changing neutral currents in the top sector

CMS Collaboration

High Energy Physics - Experiment · Submitted 10 Jun 2011

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim These limits disfavour the FCNC interpretation of the Tevatron results.

how it is stated · asserted 0.97 read the record →

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arXiv ID1106.2142 (version 2)

Pith IDRHOLT2ME, Pith's permanent record of this paper and its review

CitationCMS Collaboration. "Search for same-sign top-quark pair production at sqrt(s) = 7 TeV and limits on flavour changing neutral currents in the top sector." arXiv:1106.2142 (2011). https://pith.science/paper/RHOLT2ME

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Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 4,961 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.17 · human participants 0.01 · controlled comparison 0.14 · randomized assignment 0.01 · states quantitative result 0.30 · compares with prior results 0.80 · mentions code or data availability 0.02.

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An inclusive search for same-sign top-quark pair production in pp collisions at sqrt(s) = 7 TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 inverse picobarns. This analysis is motivated by recent studies of p p-bar to t t-bar reporting mass-dependent forward-backward asymmetries larger than expected from the standard model. These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z'). Models with such a Z' also predict enhancement of same-sign top-pair production in pp or p p-bar collisions. Limits are set as a function of the Z' mass and its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the Tevatron results.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	An inclusive search for same-sign top-quark pair production in pp collisions at sqrt(s) = 7 TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 inverse picobarns.	method 0.57	0.97	0.02	asserted 0.99
s1	This analysis is motivated by recent studies of p p-bar to t t-bar reporting mass-dependent forward-backward asymmetries larger than expected from the standard model.	background 1.00	0.04	0.02	asserted 0.97
s2	These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z').	background 0.93	0.05	0.03	hedged possibility 1.00
s3	Models with such a Z' also predict enhancement of same-sign top-pair production in pp or p p-bar collisions.	background 0.96	0.07	0.04	asserted 0.92
s4	Limits are set as a function of the Z' mass and its couplings to u and t quarks.	result 0.78	0.94	0.13	asserted 0.99
s5	These limits disfavour the FCNC interpretation of the Tevatron results.	interpretation 0.97	0.86	0.83	asserted 0.97

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from observation or experiment 0.57.

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arXiv listing abstract v2

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figures and tables
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Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

An inclusive search for same-sign top-quark pair production in pp collisions at sqrt(s) = 7 TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 inverse picobarns. This analysis is motivated by recent studies of p p-bar to t t-bar reporting mass-dependent forward-backward asymmetries larger than expected from the standard model. These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z'). Models with such a Z' also predict enhancement of same-sign top-pair production in pp or p p-bar collisions. Limits are set as a function of the Z' mass and its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the Tevatron results.

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References

How the literature uses it

39 arXiv papers cite this in 54 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 38 sentences without a confident label

Contests it 1 paper

For example, the original light $Z^'$ model [ref] is excluded by the recent CMS data on the same sign top pair production [ref] .

Chiral U(1) flavor models and flavored Higgs doublets: the top FB asymmetry and the Wjj · Introduction · contest 0.82

Uses its method or tool 1 paper

This work relies heavily on the event selections and background estimation methods of the previous CMS inclusive same-sign dilepton searches not requiring b-tagged jets in the final state [ref] .

Search for new physics in events with same-sign dileptons and b-tagged jets in pp collisions at sqrt(s) = 7 TeV · Introduction · 0.95

Uses its data or values 7 papers

Finally we enforce that the same-sign leptons (which arise due to the leptonic decays of the produced pair of same-sign tops) cross-section also remains within the LHC non-observation limits [ref] for the current data on such events.

Same-sign Tops: A Powerful Diagnostic Test for Models of New Physics · Numerical Analysis and Results · 0.85
As no excess above the SM expectation is observed, the $95%$ C.L. upper bound on the number of new-physics events were set in Ref. [ref] .

Search for top quark flavour changing neutral currents in same-sign top quark production · Results · 0.95
The CMS Collaboration announced the upper bound on the cross section for the same-sign top-quark pair production: $σ^tt < 17$ pb at 95% CL. with a luminosity of 35 pb$^-1$ [ref] , while the limit on the cross sections at ATLAS with a luminosity of $1.04$ fb$^-1$ are $σ^tt < 2$ pb at 95% CL. by using an optimized event selection for the $Z^'$ model and $σ^tt < 4$ pb at 95% CL. by using more inclusive selection, respectively [ref] .

Top A_FB at the Tevatron vs. charge asymmetry at the LHC in chiral U(1) flavor models with flavored Higgs doublets · Generalities and Inputs · 0.99

Compares with it 2 papers

The CMS collaboration has also performed a search for same-sign top quark production [ref] , however, their model-independent limit on the production cross section, 17 pb, is weaker than the above ATLAS bound.

Tracking Down the Top Quark Forward-Backward Asymmetry with Monotops · Same-sign top quark production · 0.91
This improves the previous CMS limit [ref] by a factor of 27.

Search for new physics in events with same-sign dileptons and b-tagged jets in pp collisions at sqrt(s) = 7 TeV · Models of pp to tt · 1.00

Cites it as support 2 papers

Despite the small cross section of the signal channels due to the presence of two anomalous vertices for t$t$ production, this final state has been shown to have very little SM background and is sensitive to new-physics effects [ref] .

Search for top quark flavour changing neutral currents in same-sign top quark production · Introduction · 0.98
However, flavor-changing $Z'$ exchange implies the production of same-sign top pairs at hadron colliders, which faces strong limits from the Tevatron and the LHC [ref] .

Constraints on W Prime Models for the ttbar Asymmetry · Introduction · 0.96

Cites it as background 2 papers

The main background to this signal comes from the $t t̅$ (when the events are selected without b-tagging), $t t̅+Z$ and $t t̅+W$ productions, as discussed in Refs. [ref] .

Signature of same-sign top pair production mediated by a nonuniversal $Z^\prime$ with QCD next-to-leading accuracy at the LHC · Signature and background · 0.88
Both the ATLAS and CMS collaborations have searched for anomalous production of events containing pairs of SS leptons at the LHC, using proton–proton $(pp)$ collision data at $√(s)=7,8$ and 13 [ref] .

Search for same-charge top-quark pair production in $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector · Introduction · 0.93

What it cites · 39 sentences without a confident label

Uses the method or tool of 3 papers

We used the external model interface in the MadGraph [ref] event generator to calculate at the leading order (LO) the $+j$ cross section as a function of $f_R$ and $M_$.

MadGraph/MadEvent v4: The New Web Generation · Introduction · 1.00
The fractional systematic uncertainty on the event selection efficiencies was calculated as in Ref. [ref] , and its components are summarized in Table [ref].

Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy at the LHC · Introduction · 0.95
These events were then processed by Pythia [ref] for parton showering, followed by the CMS parametrized event simulation, and the same chain of reconstruction and analysis programs used for collision data.

PYTHIA 6.4 Physics and Manual · Introduction · 1.00

Uses data or values from 1 paper

In this calculation we used the CTEQ6L [ref] parton distribution functions (PDFs), fixed the top quark mass $M_top$ to be 172.5 GeV, and set the renormalization and factorization scales to be $μ= M_top$.

New Generation of Parton Distributions with Uncertainties from Global QCD Analysis · Introduction · 0.83

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