Triple Gauge Couplings Research Articles

Probing new physics at the LHC and future colliders: SMEFT and beyond

In this talk, I review our progresses on probing new physics at the LHC and future colliders by using the Standard Model Effective Field Theory (SMEFT) and beyond. This includes to probe new physics effects in the Higgs boson couplings via leading dimension-6 operators and in the neutral triple gauge couplings (nTGCs) via leading dimension-8 operators. I also discuss the probe of Higgs self-couplings involving the SM Higgs-boson-pair plus a new heavy Higgs boson of the extended Higgs sector via the resonant diHiggs production channels.

Triple-gauge couplings in LHC diboson production: a SMEFT view from every angle

This study explores fully leptonic WZ and WW production at the LHC within the SMEFT framework at NLO in QCD, focusing on both CP-even and CP-odd triple-gauge-coupling dimension-six operators. We investigate the off-shell processes, contrasting our findings in inclusive setups with those in the presence of realistic fiducial selections. Alongside the conventional kinematic observables, we examine polarisation-sensitive observables and angular coefficients. Moreover, we assess potential SMEFT effects on asymmetry observables. Through a sensitivity analysis, we identify critical LHC observables that are particularly sensitive to SMEFT-induced modifications, thereby shedding light on potential avenues for new physics searches in diboson production at the LHC.

Composite Effective Field Theory Signal in Case of Searching for Neutral Triple Gauge Couplings with $${ZZ\rightarrow\ell\ell}{\nu\nu}$$ Production

Composite Effective Field Theory Signal in Case of Searching for Neutral Triple Gauge Couplings with $${ZZ\rightarrow\ell\ell}{\nu\nu}$$ Production

Measurements of the integrated and the differential cross sections of Z(→ℓℓ)γ production and probe for neutral triple gauge couplings

Measurements of the integrated and the differential cross sections of Z(→ℓℓ)γ production and probe for neutral triple gauge couplings

Probing neutral triple gauge couplings at the LHC and future e+e− and pp colliders

Probing neutral triple gauge couplings at the LHC and future e+e− and pp colliders

From optimal observables to machine learning: an effective-field-theory analysis of e+e−→ W+W− at future lepton colliders

We apply machine-learning techniques to the effective-field-theory analysis of the e+e− → W+W− processes at future lepton colliders, and demonstrate their advantages in comparison with conventional methods, such as optimal observables. In particular, we show that machine-learning methods are more robust to detector effects and backgrounds, and could in principle produce unbiased results with sufficient Monte Carlo simulation samples that accurately describe experiments. This is crucial for the analyses at future lepton colliders given the outstanding precision of the e+e− → W+W− measurement (~ 10−4 in terms of anomalous triple gauge couplings or even better) that can be reached. Our framework can be generalized to other effective-field-theory analyses, such as the one of e+e− → tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} or similar processes at muon colliders.

Gluon–gluon fusion contribution to the productions of three gauge bosons at the LHC

Productions of multiple gauge bosons at the LHC are sensitive to triple or quartic gauge couplings and thus provide a sensitive test for the electroweak sector of the Standard Model and allow for a probe of new physics. In this work we calculate the gluon–gluon initiate state contribution to the productions of three gauge bosons (Zγγ,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z\\gamma \\gamma ,$$\\end{document}ZZγ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ZZ\\gamma $$\\end{document} and W+W-γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^+W^-\\gamma $$\\end{document}) at the LHC, which is formally part of NNLO effects compared to the LO quark–antiquark channels corrections. For each process we present the ratio between the gluon–gluon channels contribution and the quark–antiquark channels contribution. We found that such a ratio for Zγγ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z\\gamma \\gamma $$\\end{document}(ZZγ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(ZZ\\gamma )$$\\end{document} is of the order of 10-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$10^{-3}$$\\end{document}(10-4),\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(10^{-4}),$$\\end{document} much smaller than the corresponding ratio for the diboson production due to the decrease of gluon PDF when more particles appear in the final states. These small ratios imply that gluon–gluon fusion contribution is phenomenological negligible for the productions of Zγγ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z\\gamma \\gamma $$\\end{document} and ZZγ.\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ZZ\\gamma .$$\\end{document} However, for W+W-γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^+W^-\\gamma $$\\end{document} production, the ratio is about 5%, which is of the same order of magnitude as the ratio for W+W-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^+W^-$$\\end{document} production due to the big cancellation between the amplitudes of quark–antiquark channels. While such an effect can be neglected currently at the LHC, it may be accessible at the HL-LHC.

Selection of Electroweak Physics Highlights from CMS: Measurements of Triple and Quartic Gauge Couplings

Selection of Electroweak Physics Highlights from CMS: Measurements of Triple and Quartic Gauge Couplings

Evidence of pair production of longitudinally polarised vector bosons and study of CP properties in ZZ → 4ℓ events with the ATLAS detector at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV

A study of the polarisation and CP properties in ZZ production is presented. The used data set corresponds to an integrated luminosity of 140 fb−1 of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. The ZZ candidate events are reconstructed using two same-flavour opposite-charge electron or muon pairs. The production of two longitudinally polarised Z bosons is measured with a significance of 4.3 standard deviations, and its cross-section is measured in a fiducial phase space to be 2.45 ± 0.60 fb, consistent with the next-to-leading-order Standard Model prediction. The inclusive differential cross-section as a function of a CP-sensitive angular observable is also measured. The results are used to constrain anomalous CP-odd neutral triple gauge couplings.

Search for the anomalous quartic gauge couplings through Z γ production at e − e + colliders

Spontaneous breaking of the electroweak symmetry of the standard model (SM) sets the constraints on triple and quartic gauge couplings. Therefore, the measurement of multiboson production in e − e + collisions allows us to directly test the predictions of the SM and to indirectly probe new physics beyond the SM. In this paper, we focus on the process e − e + → e − Z γ e + with Z boson decaying into neutrinos to study the anomalous quartic gauge couplings using the effective Lagrangian approach at the compact linear collider (CLIC). We obtain the sensitivities on the anomalous f T,i /Λ4 (i = 0, 2, 5, 6, 7, 8, 9) couplings taking into account the systematic uncertainties of 3, 5% at 95% Confidence Level for the CLIC with TeV. Our results show that the sensitivities on some anomalous couplings without systematic errors are up to two orders of magnitude better than the current experimental limits. Considering a realistic systematic uncertainty such as 5% from possible experimental sources, the sensitivity of all anomalous quartic couplings becomes worse by about 10% compared to those without systematic uncertainty for the CLIC.

Optimal estimation of dimension-8 neutral triple gauge couplings at the e+e− colliders

We investigate the measurement of non-standard ZZV (V = γ, Z) couplings through Z-boson pair production at the e+e− colliders. We adopt the Standard Model Effective Field Theory (SMEFT) approach to study these anomalous neutral triple gauge couplings. There are one CP-conserving and three CP-violating dim-8 SMEFT operators that contribute to ZZV couplings. Using the optimal observable technique, the sensitivity of these new physics couplings has been estimated and compared with the latest experimental limits on dim-8 couplings at the LHC at CERN. The effect of beam polarization and correlations among CP-violating ZZV couplings are discussed. The comparison of statistical limits of new physics couplings between optimal observable technique and contemporary cut-based analysis has also been studied in detail.

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%.

Anomalous triple gauge couplings in electroweak dilepton tails at the LHC and interference resurrection

We study the electroweak dilepton production with two forward jets at the LHC, aiming to measure the anomalous triple gauge couplings in the Effective Field Theory (EFT) approach. This process exhibits a distinctive feature, namely, the interference between Standard Model (SM) and beyond the SM is resurrected in the inclusive cross section of the full amplitude, including two forward jets. As a concrete illustration, we perform the detailed analytic and numerical study of the interference using a simpler toy process, and discuss the subtlety of the effective W approximation. We propose a new kinematic variable, VBFhardness, that controls the amount of energy flowing into the dilepton subprocess. We show that an appropriate cut on VBFhardness makes the interference resurrection manifest. Finally, we use the invariant mass of the dilepton system as well as the transverse momentum, as done in the literature, to derive the sensitivity to anomalous triple gauge couplings at the LHC and the high luminosity LHC. Our result is compared with the existing limits from the experiments.

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.

Revisiting Vh(→ boverline{b} ) at the LHC and FCC-hh

Diboson production processes provide good targets for precision measurements at present and future hadron colliders. We consider Vh production, focusing on the h → boverline{b} decay channel, whose sizeable cross section makes it accessible at the LHC. We perform an improved analysis by combining the 0-, 1- and 2-lepton channels with a scale-invariant b-tagging algorithm that allows us to exploit events with either a boosted Higgs via mass-drop tagging or resolved b-jets. This strategy gives sensitivity to 4 dimension-6 SMEFT operators that modify the W and Z couplings to quarks and is competitive with the bounds obtained from global fits. The benefit of the h → boverline{b} decay channel is the fact that it is the only Vh channel accessible at the LHC Run 3 and HL-LHC, while at FCC-hh it is competitive with the effectively background-free h → γγ channel assuming ≲ 5% systematic uncertainty. Combining the boosted and resolved categories yields a 17% improvement on the most strongly bounded Wilson coefficient at the LHC Run 3 with respect to the boosted category alone (and a 7% improvement at FCC-hh). We also show that, at FCC-hh, a binning in the rapidity of the Vh system can significantly reduce correlations between some EFT operators. The bounds we obtain translate to a lower bound on the new physics scale of 5, 8, and 20 TeV at the LHC Run 3, HL-LHC, and FCC-hh respectively, assuming new-physics couplings of order unity. Finally, we assess the impact of the Vh production channel on anomalous triple gauge coupling measurements, comparing with their determination at lepton colliders.

Impact of dimension-eight SMEFT operators in the electroweak precision observables and triple gauge couplings analysis in universal SMEFT

We perform a complete study of the electroweak precision observables and electroweak gauge boson pair production in terms of the SMEFT up to ${\cal O}(1/\Lambda^4)$ under the assumption of universal, C and P conserving new physics. We show that the analysis of data from those two sectors allows us to obtain closed constraints in the relevant parameter space in this scenario. In particular we find that the Large Hadron Collider data can independently constrain the Wilson coefficients of the dimension-six and -eight operators directly contributing to the triple gauge boson vertices. Our results show that the impact of dimension-eight operators in the study of triple gauge couplings is small.

Probing anomalous ZZγ and Zγγ couplings at the e+e− colliders using optimal observable technique

We study the anomalous ZZγ and Zγγ couplings that can be probed via Zγ production at the e+e− colliders. We take Standard Model Effective Field Theory (SMEFT) approach to examine these anomalous neutral triple gauge couplings in a model independent way. There are four independent dimension-8 operators that generate these gauge interactions, one of them is CP-conserving and rest three are CP-violating. We adopt optimal observable technique to extract the sensitivity at which these anomalous couplings can be probed at future e+e− colliders and then compare the results with the latest experimental limit obtained at the LHC. We also study the impact and advantage of beam polarization in these precision measurements. Statistical limit (95% C.L.) on individual anomalous couplings as well as the correlation between various couplings have been discussed in detail.

Probe of the anomalous neutral triple gauge couplings in photon-induced collision at future muon colliders

The anomalous ZZγ and Zγγ neutral triple gauge couplings occurred by dimension-eight operators are investigated through the process μ+μ−→μ+γ⁎μ−→μ+Z(νν¯)μ− at the muon collider with s=3, 6, 10 and 14 TeV. The charged lepton pseudo-rapidity, the charged lepton transverse momentum and the transverse missing energy distributions are taken in consideration for the final state of the process in the analysis. The sensitivities of the anomalous couplings are obtained at 95% Confidence Level with integrated luminosity of Lint=1, 4, 10 and 20 ab−1, respectively, according to center-of-mass energies of muon collider taking into account the effects of systematic uncertainties 0%, 3% and 5%. The best limits of anomalous CBB/Λ4, CBW/Λ4, CB˜W/Λ4 and CWW/Λ4 couplings without systematic uncertainty at center-of-mass energy of 14 TeV and integrated luminosity of 20 ab−1 are found to be [-0.01026; 0.00636] TeV−4, [-0.02482; 0.03053] TeV−4, [-0.01830; 0.02510] TeV−4, [-0.06981; 0.07387] TeV−4, respectively.

Prediction for the Anomalous ZZZ and ZZγ Couplings via two Z-boson Production at the CLIC

The non-Abelian nature of the Standard Model (SM) entails the existence of the gauge bosons' self-interactions. The gauge bosons' self-interactions are important to test the SM and see the new physics effects. These effects can be analyzed in the effective theory approach which is the main aim of this study. We examine the ZZZ and ZZγ anomalous neutral triple gauge couplings (aNTGC) via the process e^- e^+→ZZ with both unpolarized and polarized electron beam with the √s=3 TeV at CLIC. In the final state, semi-leptonic decay of Z-bosons (Z→jj , Z→ν_l (ν_l ) ̅ ) are considered. We focused on CP-violating C_BB/Λ^4 , C_BW/Λ^4 , C_WW/Λ^4 and CP-conserving C_(B ̅W)/Λ^4 couplings. The sensitivities are obtained at 95% Confidence Level with luminosities of L_int=5 ab-1, L_int=1 ab-1 and L_int=4 ab-1 for unpolarized, 80% and -80% polarized electron beams, respectively. Obtained sensitivities on anomalous couplings are 3-20 times stringent than the current experimental limits and comparable with the related phenomenological studies in the literature.

New physics in WWγ at one loop via Majorana neutrinos

Current experimental data guarantees the presence of physics beyond the Standard Model in the neutrino sector. The responsible physical description might show itself through virtual effects on low-energy observables. In particular, massive neutrinos are able to produce contributions to the triple gauge coupling $WW\gamma$. The present paper deals with the calculation, estimation and analysis of one-loop contributions from Majorana neutrinos to the Lorentz-covariant $WW\gamma$ parametrization. Our calculations show that CP-odd effects vanish exactly, whereas CP-even contributions, $\Delta\kappa$ and $\Delta Q$, remain. According to our estimations, the effects from heavy neutrinos with masses in the range of hundreds of GeVs dominate over those from light neutrinos. This investigation shows that contributions from heavy Majorana neutrinos to the anomaly $\Delta\kappa$ could be as large as $\sim{\cal O}(10^{-3})$, one order of magnitude below the Standard-Model contribution. We find that the International Linear Collider, sensitive to triple gauge couplings participating in $WW$ production, might measure these effects in electron-positron collisions at a center-of-mass energy of $800\,{\rm GeV}$, as long as heavy-neutrino masses are $\gtrsim300\,{\rm GeV}$ and below $\sim1500\,{\rm GeV}$.