Measurement of triple gauge WWγ couplings at LEP2 using photonic events

Abstract A study of events with photons and missing energy has been performed with the data sample obtained with the ALEPH detector at centre-of-mass energies from 161 to 184 GeV, corresponding to a total integrated luminosity of about 80 pb −1 . The measured distributions are in agreement with Standard Model predictions, leading to constraints on WW γ gauge coupling parameters Δ κ γ and λ γ . The results from the fit to the cross sections and to the energy and angular distributions of the photons are: Δ κ γ =0.05 +1.15 −1.10 (stat)±0.25(syst), λ γ =−0.05 +1.55 −1.45 (stat)±0.30(syst).