The exclusive two-photon production at the LHC of pairs of W and Z bosons provides a novel and unique test-ground for the electroweak gauge boson sector. In particular it offers, thanks to high gamma-gamma center-of-mass energies, large and direct sensitivity to the anomalous quartic gauge couplings otherwise very difficult to investigate at the LHC. An initial analysis has been performed assuming leptonic decays and generic acceptance cuts. Simulation of a simple counting experiment has shown for the integrated luminosity of 10 fb-1 at least four thousand times larger sensitivity to the genuine quartic couplings, a_0^W, a_0^Z, a_C^W and a_C^Z, than those obtained at LEP. The impact of the unitarity constraints on the estimated limits has been studied using the dipole form-factors. Finally, differential distributions of the decay leptons have been provided to illustrate the potential for further improvements of the sensitivities.
The search for quartic anomalous gauge couplings at LEP requires appropriate predictions for the radiative processes e+ e- \to ν\barνγγ, e+ e- \to q\bar{q}γγand e+ e- \to 4 fermions+γ. Matrix elements are exactly computed at the tree level, and the effects of anomalous couplings and initial-state radiation are included. Comparisons with results and approximations existing in the literature are shown and commented. Improved versions of the event generators NUNUGPV and WRAP are made available for experimental analysis.
We study the $W/Z$ pair production via two-photon exchange at the LHC and give the sensitivities on trilinear and quartic gauge anomalous couplings between photons and $W/Z$ bosons for an integrated luminosity of 30 and 200 fb$^{-1}$. For simplicity and to obtain lower backgrounds, only the leptonic decays of the electroweak bosons are considered. The intact protons in the final states are detected in the ATLAS Forward Proton detectors. The high energy and luminosity of the LHC and the forward detectors allow to probe beyond standard model physics and to test the higgsless and extra dimension …
Triple gauge boson production provides a promising opportunity to probe the anomalous quartic gauge couplings in understanding the details of electroweak symmetry breaking at future hadron-hadron collider facilities with increasing center of mass energy and luminosity. In this paper, we investigate the sensitivities of dimension-8 anomalous couplings related to the $ZZγγ$ and $Zγγγ$ quartic vertices, defined in the effective field theory framework, via $pp\to Zγγ$ signal process with Z-boson decaying to charged leptons at the high luminosity phase of LHC (HL-LHC) and future facilities, namely …
The anomalous quartic neutral couplings of the $γγγγ$ vertex in a polarized light-by-light scattering of the Compton backscattered photons at the CLIC are examined. Both differential and total cross sections are calculated for $e^+e^-$ collision energies 1500 GeV and 3000 GeV. The helicity of the initial electron beams is taken to be $\pm\,0.8$. The unpolarized and SM cross sections for the same values of helicities are also estimated. The 95\% C.L. exclusion limits on two anomalous photon couplings $ζ_1$ and $ζ_2$ are calculated. The best bounds on these couplings are found to be $6.85 \times…
We report on a possible measurement at the LHC using the first data and a luminosity of 10 pb$^{-1}$ of $W$ and $Z$ pair production via two-photon exchange. This measurement allows to increase the present sensitivity on $WWγγ$ and $ZZγγ$ quartic anomalous couplings from the LEP experiments by almost three orders of magnitude.
The production of $ν\barν γγ$ in high-energy $e^+e^-$ collisions offers a window on anomalous quartic gauge boson couplings. We investigate the effect of two possible anomalous couplings on the cross section for $ν\barν γγ$ production via $WW$-fusion at LEP2 ($\sqrt{s} = 200$ GeV).
This article reviews some recent developments in the analysis of anomalous triple and quartic vector boson couplings that have been discussed at the UK Phenomenology Workshop on Collider Physics 1999 in Durham.
We obtain the partial-wave unitarity constraints on the lowest-dimension effective operators which generate anomalous quartic gauge couplings but leave the triple gauge couplings unaffected. We consider operator expansions with linear and nonlinear realizations of the electroweak symmetry and explore the multidimensional parameter space of the coefficients of the relevant operators: 20 dimension-eight operators in the linear expansion and 5 ${\cal O}(p^4)$ operators in the derivative expansion. We study two-to-two scattering of electroweak gauge bosons and Higgs bosons taking into account all …
We derive one loop constraints on the anomalous quartic gauge couplings using a general non-forward dispersion relation for the elastic scattering amplitude of two longitudinally polarized vector bosons. We compare this result with another one derived by the assumption that the underlying theory satisfies the causality principle of Special Relativity and show that this latter is more constraining.
We study the process $e^+e^- \rightarrow W^+W^- γ$ at high-energy $e^+ e^-$ colliders to investigate the effect of genuine quartic $W^+W^-γγ$ and $W^+W^- Zγ$ anomalous couplings on the cross section. Deviations from the Standard Model predictions are quantified. We show how bounds on the anomalous couplings can be improved by choosing specific initial state helicity combinations. The dependence of the anomalous contributions on the collider energy is studied.
The dimension-four genuine anomalous quartic couplings are studied in processes of six-fermion production via e+e- collisions. Complete tree-level electroweak calculations are performed including initial-state-radiation and beamstrahlung. The analysis of final-state distributions can be used to find kinematical cuts to enhance the effects of anomalous couplings. For the parameters of the custodial-symmetry-conserving anomalous couplings a sensitivity in the range between 10^{-3} and 10^{-2} can be expected at 1 TeV.
We investigate the constraints on the anomalous quartic $ZZγγ$ couplings through the process $p p\to pγp\to p γq Z X$ at the LHC. Taking into consideration various forward detector acceptances and integrated LHC luminosities, we find 95% confidence level bounds on the anomalous coupling parameters. We show that the bounds on these couplings are at the order of $10^{-6}GeV^{-2}$ which are about four orders of magnitude more restricted with respect to current experimental bounds.
The production of two and three electroweak gauge bosons in the high-energy $γγ$ collisions gives the well opportunity to probe anomalous quartic gauge boson couplings. The influence of five possible anomalous couplings on the cross sections for $W^+W^-$, $W^+W^-γ$, $W^+W^-Z$ productions has been investigated at the TESLA kinematics ($\sqrt{S}\sim 1$ TeV). There are the reasonable discriminations between various anomalous contributions.
We first report on possible measurements at the LHC using the first data and a luminosity of 10 pb$^{-1}$ of $W$ and $Z$ pair production via two-photon exchange. This measurement allows in particular to increase the present sensitivity on $WWγγ$ and $ZZγγ$ quartic anomalous couplings from the LEP experiments by almost three orders of magnitude. We also discuss the possible improvements on quartic and trilinear anomalous couplings at high luminosity at the LHC using new forward proton taggers to be installed at 220 and 420 m from the CMS or ATLAS detectors.
Gauge boson self-couplings are exactly determined by the non-Abelian gauge nature of the Standard Model (SM), thus precision measurements of these couplings at the LHC provide an important opportunity to test the gauge structure of the SM and the spontaneous symmetry breaking mechanism. It is a common way to examine the physics of anomalous quartic gauge boson couplings via effective Lagrangian method. In this work, we investigate the potential of the process $pp\rightarrow pγp\rightarrow p W Z q X$ to analyze anomalous quartic $WWZγ$ couplings by two different CP-violating and CP-conserving e…
We study the W/Z pair production via two-photon exchange at the LHC and give the sensitivities on trilinear and quartic gauge anomalous couplings between photons and W/Z bosons for an integrated luminosity of 30 and 200 fb^{-1}. For simplicity and to obtain lower backgrounds, only the leptonic decays of the electroweak bosons are considered.
We analyze the anomalous quartic gauge boson couplings $WWγγ$ and $ZZγγ$, described by dimension-6 effective quartic Lagrangian at the LHC. The sensitivities to anomalous quartic gauge couplings $a_{0,c}^{W,Z}/Λ^2$ by examining the two different photon-induced processes $pp\to pγp\to p WγqX$ and $pp\to pγp\to p ZZ qX$ with $W$ and $Z$s decaying leptonically are investigated. We show that $γp$ mode of photon-induced reactions at the LHC are able to probe these couplings to the order of $10^{-6}$-$10^{-7}$ GeV$^{-2}$ at 95 % confidence level with $\sqrt s$ = 14 TeV and for proton-proton luminosi…
The absence of a light Higgs boson causes vector boson couplings to become strong at 1 TeV. A general framework for a systematic and consistent treatment is provided by effective theories of electroweak symmetry breaking. Already in next-to-leading order there appear quartic gauge couplings that go beyond the standard model and are hence called anomalous. We investigate intermediate three gauge boson states $W^+W^- Z$ and $ZZZ$ occurring in six quark production in electron positron collisions under the conditions of the International Linear Collider. We perform a sensitivity analysis of the re…
A complete list of operators contributing at the lowest order to Quartic Neutral Gauge Boson Couplings involving photons and Z-bosons, is presented. We show that, for the couplings we consider, the lowest order contribution is from dimension 8 operators in the case when a light Higgs is present and from dimension 6 operators in the higgsless case where electroweak symmetry is non-linearly realized. We also show that these operators are generated by exchange of the Kaluza-Klein partners of the graviton in extra-dimensional models. We then explore the possibility of probing these couplings in th…
The calculation of the two-loop corrections to the electroweak gauge boson quartic couplings, growing quadratically with the Higgs boson mass, is reviewed. The potential of the CERN Large Hadron Collider and e+e- linear collider to study such anomalous interactions is discussed.
All lowest-order amplitudes for e+e- --> 4f+gamma are calculated including five anomalous quartic gauge-boson couplings that are allowed by electromagnetic gauge invariance and the custodial SU(2)_c symmetry. Three of these anomalous couplings correspond to the operators L_0, L_c, and L_n that have been constrained by the LEP collaborations in WWgamma production. The anomalous couplings are incorporated in the Monte Carlo generator RACOONWW. Moreover, for the processes e+e- --> 4f+gamma RACOONWW is improved upon including leading universal electroweak corrections such as initial-state radiatio…
We analyze the potential of the Next Linear $e^+e^-$ Collider to study anomalous quartic vector-boson interactions through the processes $e^+ e^- \to W^+W^-Z$ and $ZZZ$. In the framework of $SU(2)_L \otimes U(1)_Y$ chiral Lagrangians, we examine all effective operators of order $p^4$ that lead to four-gauge-boson interactions but do not induce anomalous trilinear vertices. In our analysis, we take into account the decay of the vector bosons to fermions and evaluate the efficiency in their reconstruction. We obtain the bounds that can be placed on the anomalous quartic interactions and we study…
We investigate the constraints on the anomalous quartic $W^{+}W^{-}Zγ$ gauge boson coupling through the process $e^{-}γ\to ν_{e}W^{-}Z$. Considering incoming beam polarizations and the longitudinal and transverse polarization states of the final W and Z boson we find 95% confidence level limits on the anomalous coupling parameter $a_{n}$ with an integrated luminosity of 500 $fb^{-1}$ and $\sqrt{s}$=0.5, 1 TeV energies. We show that initial beam and final state polarizations improve the sensitivity to the anomalous coupling by up to factors of 2 - 3.5 depending on the energy.
Evaluation of anomalous couplings in the $γγ\to W^+W^-$ process needs to calculate the cross section $σ(W^+W^-)$ with a high precision. Therefore one has to consider the main contribution of high order effects. In this paper contributions of anomalous quartic boson interaction given by ${\cal L}_0$, ${\cal L}_c$, $\tilde{\cal L}_0$ are analyzed in high-energy region. Influence of high order effects is studed in dependences of $σ(W^+W^-)$ on anomalous constants and contour plots with statistical error $2δ$.
We have computed the contributions of the quartic Casimir invariants to the four-loop anomalous dimensions of twist-2 spin-N operators at N =< 16. The results provide new information on the structure of the next-to-next-to-next-to-leading order (N^3LO) splitting functions P_{ik}^(3)(x) for the evolution of parton distributions, and facilitate approximate expressions which include the quartic-Casimir contributions to the (light-like) gluon cusp anomalous dimension. These quantities turn out to be closely related, by a generalization of the lower-order `Casimir scaling', to the corresponding qua…
The production of three electroweak gauge bosons in high-energy $e^+e^-$ collisions offers a window on anomalous quartic gauge boson couplings. We investigate the effect of three possible anomalous couplings on the cross sections for $W^+W^-γ$, $Z^0Z^0γ$ and $Z^0γγ$ productions at LEP2 ($\sqrt{s} = 200$ GeV) and at a future linear collider ($\sqrt{s} = 500$ GeV). We find that the combination of energies and processes provides reasonable discrimination between the various anomalous contributions.
We study the incidence of genuine quartic vector boson couplings in the reactions e-e- -> e-e-ZZ, e-νZW, ννWW. We find that a linear collider operated in the e-e- mode will provide bounds on these couplings which are competitive with those to be obtained in the e+e- mode.
We analyze the potential of the e+e- Linear Colliders, operating in the e-gamma and gamma-gamma modes, to probe anomalous quartic vector--boson interactions through the multiple production of W's and Z's. We examine all $SU(2)_L \otimes U(1)_Y$ chiral operators of order p^4 that lead to new four--gauge--boson interactions but do not alter trilinear vertices. We show that the e-gamma and gamma-gamma modes are able not only to establish the existence of a strongly interacting symmetry breaking sector but also to probe for anomalous quartic couplings of the order of 10^{-2} at 90% CL. Moreover, t…
We analyze the potential of the CERN Large Hadron Collider to study anomalous quartic vector--boson interactions through the production of vector--boson pairs accompanied by jets. In the framework of $SU(2)_L \otimes U(1)_Y$ chiral Lagrangians, we examine all effective operators of order $p^4$ that lead to new four--gauge--boson interactions but do not alter trilinear vertices. In our analyses, we perform the full tree level calculation of the processes leading to two jets plus vector--boson pairs, $W^+W^-$, $W^\pm W^\pm$, $W^\pm Z$, or $ZZ$, taking properly into account the interference betwe…
We study the sensitivity to anomalous quartic $ZZγγ$ couplings through the processes $e^{+}e^{-}\rightarrow Z\, Z\, γ$, $e^{+}e^{-} \rightarrow e^{+}γ^{*} e^{-} \rightarrow e^{+} Z\, Z\, e^{-}$ and $e^{+}e^{-} \rightarrow e^{+}γ^{*} γ^{*} e^{-} \rightarrow e^{+}\, Z\, Z\, e^{-}$ at the CLIC. We find $95\%$ confidence level bounds on these coupling parameters defining by the dimension-six operators. The best bounds on the anomalous $ZZγγ$ couplings among the three processes are obtained from $e^{+}e^{-}\rightarrow Z\, Z\, γ$ at a center of mass energy of $3$ TeV and an integrated luminosity of …
We study the constraints on the vertices $W^+W^- Zγ$, $W^+W^-γγ$, and $ZZγγ$ that can be obtained from triple-gauge-boson production at the next generation of linear $e^+e^-$ colliders operating in the $γγ$ mode. We analyze the processes $γγ\to W^+W^-V$ ($V=Z$, or $γ$) and show that these reactions increase the potential of $e^+e^-$ machines to search for anomalous four-gauge-boson interactions.
Composite effective field theory signal from anomalous quartic gauge couplings for $ZZ(\rightarrow\ell\ellνν)jj$ and $Zγ(\rightarrowννγ)jj$ productions
The production of several vector bosons in $γγ$-interactions is the best place to search directly for any anomalous behavior of triple and quartic couplings. A few anomalous quartic boson operators are considered in the paper. A high precision of anomalous effects can be achieved by calculation of the lowest order electroweak corrections: one-loop corrections, real photon and $Z$-boson emission.
The constraints on the anomalous quartic $WWγγ$ and $ZZγγ$ gauge boson couplings are investigated through the processes $eγ\to W^{-}γν_{e}$ and $eγ\to Zγe$. Considering the longitudinal and transverse polarization states of the final W or Z boson and incoming beam polarizations we find 95% confidence level limits on the anomalous coupling parameters $a_{0}$ and $a_{c}$ with an integrated luminosity of 500 $fb^{-1}$ and $\sqrt{s}$=0.5, 1 TeV energies. Assuming the $W^{+}W^{-}γγ$ couplings are independent of the $ZZγγ$ couplings we show that the longitudinal polarization state of the final gauge…
Triple gauge boson associated production at the LHC serves as an interesting channel to test the robustness of the Standard Model. Any deviation from its SM prediction may indicate possible existence of relevant new physics, e.g., anomalous quartic gauge boson couplings. In this paper, a Monte-Carlo feasibility study of measuring WWA production with pure leptonic decays and probing anomalous quartic gauge-boson (e.g., WWAA) couplings, is presented in detail for the first time, with parton shower and detector simulation effects taken into account. Our results show that at the sqrt{s} = 14 TeV L…
In this paper, we examine the potentials of the processes $γγ\rightarrow W^{+} W^{-}Z $ and $e^{+}e^{-} \rightarrow e^{+}γ^{*} γ^{*} e^{-} \rightarrow e^{+} W^{+} W^{-} Z e^{-}$ at the CLIC with $\sqrt{s}=0.5,1.5$ and $3$ TeV to investigate anomalous quartic $WWZγ$ couplings by two different CP-violating and CP-conserving effective Lagrangians. We find $95\%$ confidence level limits on the anomalous coupling parameters at the three CLIC energies and various integrated luminosities. The best limits obtained from the process $γγ\rightarrow W^{+} W^{-}Z $ on the anomalous $\frac{k_{0}^{W}}{Λ^{2}}…
We find 95% confidence level limits on the anomalous coupling parameters $a_0$, $a_c$ and $a_n$ with an integrated luminosity of $500fb^{-1}$ and $\sqrt s =0.5, 1$ and 1.5 TeV energies. We take into account incoming beam polarizations and also the final state polarizations of the gauge bosons in the cross-section calculations to improve the bounds. We show that polarization leads to a significant amount of improvement in the sensitivity limits.
We analyze the potential of the CERN Large Hadron Collider (LHC) to study anomalous quartic vector-boson interactions Z Z gamma gamma, Z Z Z gamma, W+ W- gamma gamma, and W+ W- Z gamma through the weak boson fusion processes q q -> q q gamma gamma and q q -> q q gamma Z(-> l+ l-) with l = electron or muon. After a careful study of the backgrounds and how to extract them from the data, we show that the process p p -> j j gamma l+ l- is potentially the most sensitive to deviations from the Standard Model, improving the sensitivity to anomalous couplings by up to a factor 10^4 (10^2) with respect…
We analyze the potential of the Fermilab Tevatron and CERN Large Hadron Collider (LHC) to study anomalous quartic vector--boson interactions (photon photon Z Z) and (photon photon W+ W-). Working in the framework of SU(2)_L X U(1)_Y chiral Lagrangians, we study the production of photons pairs accompanied by (e+e-), (e nu), and jet pairs to impose bounds on these new couplings, taking into account the unitarity constraints. We compare our findings with the indirect limits coming from precision electroweak measurements as well as with presently available direct searches at LEPII. We show that th…
We conducted a study on measuring $W^+W^-$ production and on the sensitivity limits at $95\%$ Confidence Level on thirteen anomalous couplings obtained by dimension-8 operators which are related to the anomalous quartic $WWγγ$ couplings. We consider the main $e^-p \to e^-γ^*γ^*p \to e^-W^+W^-p$ reaction with the sub-process $γ^*γ^* \to W^+W^-$ at the Large Hadron electron Collider (LHeC) and the Future Circular Collider-hadron electron (FCC-he). For the LHeC, energies of the $e^-$ beams are taken to be $E_e =60$ and 140 GeV and the energy of the $p$ beams is taken to be $E_p = 7$ TeV. For the …
Gauge boson self-couplings are completely defined by the non-Abelian gauge symmetry of the Standard Model (SM). For this reason, a direct search for these couplings is extremely significant in understanding the gauge structure of the SM. The possible deviation from the SM predictions of gauge boson self-couplings would be a sign of the presence of new physics beyond the SM. In this work, we study the sensitivities on the anomalous couplings defined by dimension-8 operators related to the $ZZγγ$ and $Zγγγ$ quartic vertices through the process $e^+e^- \to Zγγ$ with Z-boson decaying to charged le…
We have investigated the anomalous quartic couplings defined by the dimension-8 operators in semileptonic decay channel of the $e^{+}e^{-}\rightarrow ν_{e} W^{-} W^{+} \barν_{e}$ process for unpolarized and polarized electron (positron) beam at the Compact Linear Collider. We give the $95\%$ confidence level bounds on anomalous $\frac{f_{S0}}{Λ^{4}}$, $\frac{f_{S1}}{Λ^{4}}$ and $\frac{f_{T0}}{Λ^{4}}$ couplings for various values of the integrated luminosities and center-of-mass energies. The best sensitivities obtained on anomalous $\frac{f_{S0}}{Λ^{4}}$, $\frac{f_{S1}}{Λ^{4}}$ and $\frac{f_{T…
In this thesis we investigated, at partonic level and leading order, the LHC potencial operating with $\sqrt{s}=14$ TeV and integrated luminosity of $L=100\;{fb}^{-1}$ to probe "pure" (without triple vertex contributions) anomalous electroweak quartic couplings, $WWWW$ and $WWZZ$, in the semileptonic $pp \rightarrow l^{\pm}ν_{l}jjjj$ channel, enhanced by the Vector Boson Fusion collider signatures. Deviations on SM quartic couplings were parameterized in a model independent approach, realized linearly ($L_{S0}$ and $L_{S1}$ operators) or not ($L_{4}$ and $L_{5}$ operators), on the basis of eff…
We describe the reaches on quartic $γγγγ$, $γγWW$, $γγZZ$, $γγγZ$, $γγt \bar{t}$ anomalous couplings at the LHC using intact protons in the final state measured in AFP in ATLAS or PPS in CMS-TOTEM.
We describe different physics topics which can be performed at the LHC using tagged intact protons, namely a better understanding of the Pomeron structure in terms of quarks and gluons, and the serach for quartic anomalous couplings.
The Large Hadron Electron Collider and the Future Circular Collider-hadron electron with high center-of-mass energy and luminosity allow to better understand the Standard Model and to examine new physics beyond the Standard Model in the electroweak sector. Multi-boson processes permit for a measurement of the gauge boson self-interactions of the Standard Model that can be used to determine the anomalous gauge boson couplings. For this purpose, we present a study of the process $ep \rightarrow ν_{e} γγj$ at the Large Hadron Electron Collider with center-of-mass energies of 1.30, 1.98 TeV and at…
In this paper, the potentials of two different processes $e^{+}e^{-}\rightarrow W^{-} W^{+}γ$ and $e^{+}e^{-} \rightarrow e^{+}γ^{*} e^{-} \rightarrow e^{+} W^{-} Z ν_{e}$ at the Compact Linear Collider (CLIC) are examined to probe the anomalous quartic $WWZγ$ gauge couplings. For $\sqrt{s}=0.5, 1.5$ and 3 TeV energies at the CLIC, $95\%$ confidence level limits on the anomalous coupling parameters defining the dimension-six operators are found via the effective Lagrangian approach in a model independent way. The best limits on the anomalous couplings $\frac{k_{0}^{W}}{Λ^{2}}$, $\frac{k_{c}^{W…
Probing anomalous quartic gauge couplings in same-sign $W$ boson scattering with polarization and spin correlation
Instituto de Física, Universidade de São Paulo（圣保罗大学物理研究所）；Wilczek Quantum Center, Shanghai Institute for Advanced Studies（上海高等研究院费曼量子中心）；University of Science and Technology of China（中国科学技术大学）
We study the production of gauge boson pairs at the next generation of linear $e^+e^-$ colliders operating in the $eγ$ mode. The processes $eγ\rightarrow VV^\prime F$ ($V,V^\prime =W$, $Z$, or $γ$ and $F=e$ or $ν$) can give valuable information on possible deviations of the quartic vector boson couplings from the Standard Model predictions. We establish the range of the new couplings that can be explored in these colliders based on a $3σ$ effect in the total cross section. We also present several kinematical distributions of the final state particles that could manifest the underlying new dyna…
We obtain the constraints on possible anomalous quartic vector-boson vertices arising from the precision measurements at the $Z$ pole. In the framework of $SU(2)_L \otimes U(1)_Y$ chiral Lagrangians, we examine all effective operators of order $D=4$ that lead to four-gauge-boson interactions but do not induce anomalous trilinear vertices. We constrain the anomalous quartic interactions by evaluating their one-loop corrections to the $Z$ pole physics. Our analysis is performed in a generic $R_ξ$ gauge and it shows that only the operators that break the $SU(2)_C$ custodial symmetry get limits cl…
