Anomalous WWγ Research Articles

Projected sensitivity to dimension-6 triple gauge couplings at the FCC-hh

In this study, we investigate the process pp→W±γ for the physics potential of the FCC-hh with s=100 TeV to examine the anomalous WWγ couplings defined by three CP-conserving and two CP-violating effective operators of dimension-6. The analysis containing the realistic detector effects is carried out in the mode where W± bosons in the final state decay into the leptonic channel. The best sensitivities obtained from the process pp→W±γ on the anomalous couplings CWWW/Λ2 and CW,B/Λ2 determined by CP-conserving effective Lagrangians are [−0.010;0.010] TeV−2 and [−0.40;0.41] TeV−2, while CW˜WW/Λ2 and CW˜/Λ2 couplings defined by CP-violating effective Lagrangian are obtained as [−0.003;0.003] TeV−2 and [−0.32;0.33] TeV−2 at the FCC-hh with Lint=30 ab−1. However, if the systematic uncertainty is included, we obtain reduced sensitivities on the anomalous WWγ coupling. The results are compared for assumed systematics of 5% and 10%.

Investigation of anomalous triple gauge couplings in μγ collision at multi-TeV muon colliders

The pursuit of discovery in particle physics has always required study at the highest possible energies. Multi-TeV muon colliders, which have important advantages, offer unprecedented potential for investigating new physics beyond the Standard Model. We extensively assume a range of center-of-mass energies from 3 to 30 TeV and a range of integrated luminosities from 1 to 90 ab−1 for future multi-TeV muon colliders. We perform a phenomenological study of the anomalous WWγ couplings via the process [Formula: see text] using a model-independent analysis in the effective field theory framework at multi-TeV muon colliders. The sensitivity estimates obtained for the anomalous WWγ couplings at systematic uncertainties of δsys = 0%, 3%, 5% are compared with the experimental results. Our best sensitivity limits at 95% confidence level for cWWW/Λ2, [Formula: see text], c B /Λ2, c W /Λ2, and [Formula: see text] couplings are [−0.030; 0.025], [−0.014; 0.014], [−0.185; 0.187], [−0.187; 0.189], and [−1.177; 1.097] TeV−2 at the multi-TeV muon collider with center-of-mass energy of 30 TeV and integrated luminosity of 90 ab−1, respectively.

Search for the anomalous WWγ couplings through the process [formula omitted] at ILC with unpolarized and polarized beams

We investigate the anomalous W+W−γ couplings through the process e−e+→νeν‾eγ for unpolarized and polarized electron (positron) beams at the International Linear Collider. We give the 95% Confidence Level limits on the anomalous couplings with and without the systematic uncertainties for various values of center-of-mass energies and the integrated luminosities. We show that the obtained limits on the anomalous couplings through the process e−e+→νeν‾eγ can highly improve the current experimental limits.

Search for anomalous triple gauge couplings in WW and WZ production in lepton + jet events in proton-proton collisions at sqrt{s} = 13 TeV

A search is presented for three additional operators that would lead to anomalous WWγ or WWZ couplings with respect to those in the standard model. They are constrained by studying events with two vector bosons; a W boson decaying to eν or μν, and a W or Z boson decaying hadronically, reconstructed as a single, massive, large- radius jet. The search uses a data set of proton-proton collisions at a centre-of-mass energy of 13 TeV, recorded by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 35.9 fb−1. Using the reconstructed diboson invariant mass, 95% confidence intervals are obtained for the anomalous coupling parameters of −1.58 < cWWW/Λ2< 1.59 TeV−2, −2.00 < cW/Λ2< 2.65 TeV−2, and −8.78 < cB/Λ2< 8.54 TeV−2, in agreement with standard model expectations of zero for each parameter. These are the strictest bounds on these parameters to date.

Anomalous WWγ couplings with beam polarization at the Compact Linear Collider

We study the anomalous WWγ couplings at the Compact Linear Collider through the processes e+e−→W+W−, e−e+→e−γ⁎e+→e+νeW− and e−e+→e−γ⁎γ⁎e+→e−W+W−e+ (γ⁎ is the Weizsacker–Williams photon). We give the 95% confidence level limits for unpolarized and polarized electron (positron) beam on the anomalous couplings for various values of the integrated luminosities and center-of-mass energies. We show that the obtained limits on the anomalous couplings through these processes can highly improve the current experimental limits. In addition, our limits with beam polarization are approximately two times better than the unpolarized case.

Measurement of theWγandZγinclusive cross sections inppcollisions ats=7 TeVand limits on anomalous triple gauge boson couplings

Measurements of Wγ and Zγ production in proton-proton collisions at s=7 TeV are used to extract limits on anomalous triple gauge couplings. The results are based on data recorded by the CMS experiment at the LHC that correspond to an integrated luminosity of 5.0 fb−1. The cross sections are measured for photon transverse momenta pTγ>15 GeV, and for separations between photons and final-state charged leptons in the pseudorapidity-azimuthal plane of ΔR(ℓ,γ)>0.7 in ℓνγ and ℓℓγ final states, where ℓ refers either to an electron or a muon. A dilepton invariant mass requirement of mℓℓ>50 GeV is imposed for the Zγ process. No deviations are observed relative to predictions from the standard model, and limits are set on anomalous WWγ, ZZγ, and Zγγ triple gauge couplings.8 MoreReceived 31 August 2013DOI:https://doi.org/10.1103/PhysRevD.89.092005This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.© 2014 CERN, for the CMS Collaboration

Measurement of the W+W− cross section in pp collisions at $\sqrt{s} = 7\mbox{ TeV}$ and limits on anomalous WWγ and WWZ couplings

A measurement of W+W− production in pp collisions at $\sqrt{s} = 7~\mathrm{TeV}$ is presented. The data were collected with the CMS detector at the LHC, and correspond to an integrated luminosity of 4.92±0.11 fb−1. The W+W− candidates consist of two oppositely charged leptons, electrons or muons, accompanied by large missing transverse energy. The W+W− production cross section is measured to be 52.4±2.0 (stat.)±4.5 (syst.)±1.2 (lum.) pb. This measurement is consistent with the standard model prediction of 47.0±2.0 pb at next-to-leading order. Stringent limits on the WWγ and WWZ anomalous triple gauge-boson couplings are set.

Limits on anomalous trilinear gauge couplings at the CMS with 7 TeV Large Hadron Collider data

Diboson production in proton–proton collisions presents an opportunity to study the self-interaction between gauge bosons via anomalous trilinear gauge couplings (aTGC). The values of these couplings are fully fixed in the SM by the gauge structure. Thus, any deviation of the observed strength of the TGC from the SM prediction would indicate new physics. This paper presents the limits on anomalous WWγ, ZZγ and Zγ γ trilinear gauge couplings in proton–proton collisions at the centre of mass energy of 7 TeV with the CMS detector.

Measurement of Wγ and Zγ production cross sections in pp collisions at [formula omitted] and limits on anomalous triple gauge couplings with the ATLAS detector

This Letter presents measurements of l±νγ and l+l−γ (l=e,μ) production in 1.02 fb−1 of pp collision data recorded at s=7 TeV with the ATLAS detector at the LHC in the first half of 2011. Events dominated by Wγ and Zγ production with leptonic decays of the W and Z bosons are selected, and their production cross sections and kinematic properties are measured in several ranges of the photon transverse energy. The results are compared to Standard Model predictions and are used to determine limits on anomalous WWγ and ZZγ/Zγγ couplings.

Wγ AND Zγ PRODUCTION AND LIMITS ON ANOMALOUS WWγ, ZZγ AND Zγγ COUPLINGS WITH D0 DETECTOR

The recent D0 results on Wγ and Zγ production are presented. First, the cross-section and the difference in rapidities between photons and charged leptons for inclusive W(→lν)+γ production in eγ and μγ final states are discussed, then are the cross-section and differential cross-section as a function of photon transverse momentum for Zγ→l+l-(l = e, μ) process. Finally, I present the limits on anomalous WWγ, ZZγ and Zγγ couplings.

WγProduction and Limits on AnomalousWWγCouplings inpp¯Collisions ats=1.96 TeV

We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(→lν) + γ production in eγ and μγ final states. Using data corresponding to an integrated luminosity of 4.2 fb(-1) collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp → Wγ + X → lνγ + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WWγ couplings for data from hadron colliders: -0.4<Δκ(γ)<0.4 and -0.08<λ(γ)<0.07 at the 95% C.L.

Measurement of Wγ and Zγ production in pp collisions at [formula omitted

A measurement of Wγ and Zγ production in proton–proton collisions at s=7 TeV is presented. Results are based on a data sample recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 36 pb−1. The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy ETγ>10 GeV and spatial separation from charged leptons in the plane of pseudorapidity and azimuthal angle ΔR(ℓ,γ)>0.7, and with an additional dilepton invariant mass requirement of Mℓℓ>50 GeV for the Zγ process. The following cross section times branching fraction values are found: σ(pp→Wγ+X)×B(W→ℓν)=56.3±5.0(stat.)±5.0(syst.)±2.3(lumi.) pb and σ(pp→Zγ+X)×B(Z→ℓℓ)=9.4±1.0(stat.)±0.6(syst.)±0.4(lumi.) pb. These measurements are in agreement with standard model predictions. The first limits on anomalous WWγ, ZZγ, and Zγγ trilinear gauge couplings at s=7 TeV are set.

Limits on anomalousWWγandWWZcouplings fromWW/WZ→eνjjproduction

Limits on anomalous WWγ and WWZ couplings are presented from a study of WW/WZ→eνjj events produced in pp¯ collisions at s=1.8 TeV. Results from the analysis of data collected using the DØ detector during the 1993–1995 Tevatron collider run at Fermilab are combined with those of an earlier study from the 1992–1993 run. A fit to the transverse momentum spectrum of the W boson yields direct limits on anomalous WWγ and WWZ couplings. With the assumption that the WWγ and WWZ couplings are equal, we obtain −0.34<λ<0.36 (with Δκ=0) and −0.43<Δκ<0.59 (with λ=0) at the 95% confidence level for a form-factor scale Λ=2.0 TeV. Received 15 December 1999DOI:https://doi.org/10.1103/PhysRevD.62.052005©2000 American Physical Society

Can HERA data improve the LEP constraints on the WWV vertex?

The combined results from ep → νWX, ep → eWX, and ep → νγX processes at HERA are used to constrain anomalous three-boson couplings. The effective model for anomalous couplings where there is no light Higgs boson and where interactions responsible for the breakdown of electroweak symmetry are strongly coupled is considered. Bounds on the couplings L9L and L9R, which parametrize contributions from the anomalous WWγ (WWZ) vertices, attainable from an analysis of the distributions for the processes in question are presented. The results are compared with the bounds resulting from the LEP I and LEP II data. It is shown that the bounds coming from HERA significantly reduce the parameter region allowed by the analysis of the LEP I and LEP II data.

Library of SM and anomalous [formula omitted] couplings for the [formula omitted] Monte Carlo programs

A brief description of the library of the Standard Model and anomalous WWγ coupling contribution to the matrix element for e +e −→ν ν ̄ nγ process is given. It can be used with any Monte Carlo program for e +e −→f f ̄ nγ processes. A working example of the application for the KORALZ version 4.04 is also provided.

Exotic searches with the ZEUS detector

Exotic Searches have been performed using the ZEUS detector at HERA. Results from a resonance search are presented in terms of Leptoquark and R-parity violating SUSY interpretations, using an event sample corresponding to 47 pb −1 of e + p data taken between 1994 and 1997. No significant evidence for a resonance was found in either scenario and limits were derived for leptoquark and squark production. The first measurement of the W production cross section in ep collisions is summarized. An explicit upper limit on the W production cross section has been derived and has been translated into constraints on anomalous WWγ couplings. Finally, preliminary results are shown for the e − p data collected in 1998 and 1999 at HERA. No deviations from the Standard Model were observed both in a search for events with an isolated high P T lepton and in the high- Q 2 neutral current (NC) analyses.

CP-violating anomalous WWγ couplings in e+e− collisions

We investigate the sensitivity of future linear collider experiments to CP violating WWγ couplings in the process e +e −→ν ν ̄ γ . We consider several sets of machine parameters: centre of mass energies s = 350, 500 and 800 GeV and operating at different luminosities. From an analysis of the differential cross-section the following 95% C.L. limits | κ ̃ γ|<0.18 , | λ ̃ γ|<0.069 are estimated to be obtained at a future 500 GeV LC with an integrated luminosity of 125 fb −1 , a great improvement as compared to the LEP2 reach, where a sensitivity of order 2 for both couplings is found.

Higher-order QED corrections to $$e^ + e^ - \to v\bar v\gamma $$ at LEP2

The process \(e^ + e^ - \to v\bar v + \gamma \) with a distinctive “photon-plus-missing-energy” signal can serve as an important tool to search for new physics at LEP2. It can be exploited to measure the WWγ coupling, or to search for weakly interacting and invisible (s)particles. For meaningful comparisons of experimental data with theoretical predictions, higher-order QED corrections due to multiphoton emission must be taken into account. In the present paper we explain how the WWγ coupling has been incorporated into the KORALZ Monte Carlo program, which can now be used for simulations of \(e^ + e^ - \to v\bar v + \gamma \) events with higher-order QED corrections. The strategy of how to perform an experimental analysis in the presence of experimental cuts is proposed. The question of systematic uncertainties is addressed and some numerical results for the phenomenologically interesting case of anomalous WWγ couplings are also given.

Limits on anomalousWWγandWWZcouplings

Limits on the anomalous WWγ and WWZ couplings are presented from a simultaneous fit to the data samples of three gauge boson pair final states in pp collisions at √s=1.8TeV: Wγ production with the W boson decaying to eν or μν, W boson pair production with both of the W bosons decaying to eν or μν, and WW or WZ production with one W boson decaying to eν and the other W boson or the Z boson decaying to two jets. Assuming identical WWγ and WWZ couplings, 95% C.L. limits on the anomalous couplings of -0.30<Δκ<0.43 (λ=0) and -0.20<λ<0.20 (Δκ=0) are obtained using a form factor scale Λ=2.0TeV. Limits found under other assumptions on the relationship between the WWγ and WWZ couplings are also presented.

Boson pair production and triple gauge couplings

The DØ and CDF Collaborations measure boson pair production including Wγ, WW, WZ, ZZ and Zγ production in pp̄ Wγ, WW, and Zγ production cross sections and limits on non-Standard Model triple gauge boson couplings. The limits on anomalous WWγ, WWZ, Zγγ and ZZγ couplings are the most restrictive available. Prospects for Run II are discussed.