Professor Tony Weidberg

Abstract:

The process t→H+b, H+→τ+v, τ+→hadrons+v and its charge conjugate are investigated by seeking an excess in number of observed τ's beyond that expected from the standard model under the assumption of e-τ universality. No such excess is found and new regions of the mH-mt plane are excluded for B(H+→τv) = 0.5 and 1.0. In addition, the ratio of couplings of the τ and e to the W is precisely measured as gwτ/gwe = 1.02 ± 0.04(stat.)±0.04(syst.). © 1992.

Abstract:

The process pp→evγ+X is studied as √s=630 GeV. The observed signal is used to extract a direct measurement of the parameters κ and λ which define the magnetic dipole and electric quadrupole moments of the W boson and therefore the WWγ coupling. We find κ=1+2.6-2.2 and λ=0+1.7-1.8 and their 95% confidence limits -3.5<κ<5.9 and -3.6<λ<3.5. The results are model indepedent and in good agreement with the standard model values, κ=1 and λ=0. © 1992.

Abstract:

Results are given on a search for the decay W±→π±γ with the UA2 detector in pp collisions at √s=630 GeV. No signal for such a process is observed and upper limits on the ration R=Γ(W±→π±γ)/ Γ(W±→e±v)<4.9× 10-3 and on the branching ratio BR(W±→π±γ)<5. 4×10-4 are derived at 95% confidence level. © 1992.

Abstract:

Results on the cross section for the production of electron pairs in pp collisions at √s = 630 GeV are presented. The measured value is σ = 405 ± 51 (syst.) ± 84 (syst.) pb, in the invariant mass interval 10 < m< 70 GeV. The results are compared to recent theoretical calculations which include O(αs2) QCD contributions. The comparison of these data with those of lower energy experiments show approximate scaling as a function of the variable √τ = m √s. © 1992.