Measurement of charged current triple gauge boson couplings using W pairs at LEP

Triple gauge boson couplings are measured from W-pair events recorded by the OPAL detector at LEP at centre-of-mass energies of 183 - 209 GeV with a total integrated luminosity of 680 pb^-1. Only CP-conserving couplings are considered and SU(2) x U(1) relations are used, resulting in four independent couplings, and g^z₅. Determining each coupling in a separate fit, assuming the other couplings to take their Standard Model values, we obtain , g^z₁ = 0.987 ^{+ 0.034}_-0.033, and g^z₅ = -0.04 ^{+ 0.13}_-0.12, where the errors include both statistical and systematic uncertainties. Fits are also performed allowing some of the couplings to vary simultaneously. All results are consistent with the Standard Model predictions.Received: 14 July 2003, Published online: 9 March 2004     

Measurement of triple gauge boson couplings at an $e\gamma$-collider

If no light Higgs boson exists, the interaction among the gauge bosons becomes strong at high energies ( ). The effects of strong electroweak symmetry breaking (SEWSB) could manifest themselves indirectly as anomalous couplings before they give rise to new physical states like resonances. Here a study of the measurement of trilinear gauge couplings is presented looking at the hadronic decay channel of the W boson at an -collider. A sensitivity in the range of 10^-3 to 10^-4 can be reached depending on the coupling under consideration.Received: 5 October 2004, Published online: 17 December 2004     

Measurement of the ZZ production cross section and limits on anomalous neutral triple gauge couplings in proton-proton collisions at sqrt[s] = 7 TeV with the ATLAS detector

A measurement of the ZZ production cross section in proton-proton collisions at sqrt[s] = 7 TeV using data corresponding to an integrated luminosity of 1.02 fb(-1) recorded by the ATLAS experiment at the LHC is presented. Twelve events containing two Z boson candidates decaying to electrons and/or muons are observed, with an expected background of 0.3 ± 0.3(stat)(-0.3)(+0.4)(syst) events. The cross section measured in a phase-space region with good detector acceptance and for dilepton masses within the range 66 to 116 GeV is σ(ZZ → ?+ ?- ?+ ?-)(fid) = 19.4(-5.2)(+6.3)(stat)(-0.7)(+0.9)(syst) ± 0.7(lumi) fb. The resulting total cross section for on-shell ZZ production, σ(ZZ)(tot) = 8.5(-2.3)(+2.7)(stat)(-0.3)(+0.4)(syst) ± 0.3(lumi) pb, is consistent with the standard model expectation of 6.5(-0.2)(+0.3) pb calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived.     

Study of the gluonic quartic gauge couplings at muon colliders

The potential of muon colliders opens up new possibilities for the exploration of new physics beyond the Standard Model. It is worthwhile to investigate whether muon colliders are suitable for studying gluonic quartic gauge couplings(gQGCs), which can be contributed by dimension-8 operators in the framework of the Standard Model effective field theory, and are intensively studied recently. In this paper, we study the sensitivity of the process ■ gQGCs.Our results indicate that the muon colliders...     

Contribution to ε′/ε from anomalous gauge couplings

Recently the KTev Collaboration has measured Re (ε′/ε)=(28±4.1)×10⁻⁴ which is in agreement with early measurements from NA31. The Standard Model prediction for ε′/ε is on the lower end of the experimentally allowed range depending on models for hadronic matrix elements. In this paper we study the contributions from anomalous gauge couplings. We find that the contributions from anomalous couplings can be significant and can enhance ε′/ε to have a value closer to data.     

\mathrm{W^+W^-} production and triple gauge boson couplings at LEP energies up to 183 GeV

A study of W-pair production in annihilations at LEP is presented, based on candidates corresponding to an integrated luminosity of 57 pb at GeV. Assuming that the angular distributions of the W-pair production and decay, as well as their branching fractions, are described by the Standard Model, the W-pair production cross-section is measured to be pb. Assuming lepton universality and combining with our results from lower centre-of-mass energies, the W branching fraction to hadrons is determined to be %. The number of W-pair candidates and the angular distributions for each final state (, are used to determine the triple gauge boson couplings. After combining these values with our results from lower centre-of-mass energies we obtain , and , where the errors include both statistical and systematic uncertainties and each coupling is determined by setting the other two couplings to the Standard Model value. The fraction of W bosons produced with a longitudinal polarisation is measured to be . All these measurements are consistent with the Standard Model expectations. Received: 23 October 1998 / Published online: 1 March 1999     

Measurement of the mass and the width of the W boson at LEP

The mass and the total decay width of the W boson are measured with the L3 detector at the LEP e⁺e^– collider using W-boson pairs produced in 0.7 fb^–1 of data collected at centre-of-mass energies between 161 and 209 GeV. Combining semi-leptonic and fully-hadronic final states, the mass and the width of the W boson are determined to be

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

Diboson production in proton?Cproton 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 WW??, ZZ?? and Z?? ?? trilinear gauge couplings in proton?Cproton collisions at the centre of mass energy of 7 TeV with the CMS detector.     

Radiative decay of the bottom quark and the WWγ coupling

The flavour-changing radiative decay b→sγ is analysed, and is found to be sensitive to the WWγ coupling. QCD corrections are found to play an important role. A good measurement of the branching ratio for B→K*γ may allow us to test the gauge coupling for WWγ of the standard model.     

Measurement of the single-jet invariant cross section at Fermilab

In an experiment performed at Fermilab we have studied the production of high p_t hadron jets from 400 GeV/c pp interactions. A large solid-angle, towered calorimeter was used to trigger and reconstruct the jet events. We report results for inclusive single-jet production and compare those results with QCD predictions and results obtained at the ISR and the SPS Collider.