Improved measurement of the Triple-Gauge-Boson Couplings $\gamma WW$ and ZWW in $e^+ e^-$ collisions

Abstract : Triple gauge-boson couplings WWgamma and WWZ involving single-photon, single-W and W-pair production are determined using data samples collected at LEP with the ALEPH detector at centre-of-mass energies between 183 and 209 GeV. The integrated luminosity used is 700 pb-1 for the single-photon measurement and 683 pb-1 for the W channels. Restricting the measurement to C- and P- conserving terms and applying local SU(2)xU(1) gauge invariance, the measured values of the parameters g1z, kappa_gamma and lambda_gamma are: g1z = 1.001 +/- 0.027(stat.) +/- 0.013(syst.) kappa_gamma = 0.971 +/- 0.055(stat.) +/- 0.030(syst.) lambda_gamma = -0.012 +/- 0.027(stat.) +/- 0.011(syst.) for single-parameter fits, where the two other parameters are fixed to their Standard Model values. Results are also presented for the cases where two or all three couplings are allowed to vary. An additional analysis using W-pair events is performed to measure the unconstrained real and imaginary parts of all 14 triple gauge-boson couplings and to perform an indirect search for a techni-rho resonance. No deviations from the Standard Model expectations are observed and the lower limit on the techni-rho mass is set to 600 GeV/c2 at 95% confidence level.
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Journal articles

Cited literature [18 references]

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Submitted on : Tuesday, March 1, 2005 - 1:56:46 PM
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Citation

S. Schael, R. Barate, R. Brunelière, I. de Bonis, D. Décamp, et al.. Improved measurement of the Triple-Gauge-Boson Couplings $\gamma WW$ and ZWW in $e^+ e^-$ collisions. Physics Letters B, Elsevier, 2005, 614, pp.7-26. ⟨10.1016/j.physletb.2005.03.058⟩. ⟨in2p3-00023825⟩

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