arXiv subjects
Publications and source records attributed to Anja Werthenbach.
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).
The vanishing of the cross section for particular points in phase space - radiation zeros - is examined for the process $ q \bar q \to W^+W^- γ$ at high energy. For photon energies that are not too large, the cross section does exhibit deep dips in regions of phase space corresponding to the position of the actual zeros. We show that in these regions the sensitivity to possible anomalous quartic couplings is very large.
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.
The vanishing of the cross section for particular points in phase space - radiation zeros - is examined for the process $ q \bar q \to W^+W^- γ$ at high energy. Unlike the process $q \bar q' \to W^\pm γ$, actual zeros only occur in the soft-photon limit. However, for photon energies that are not too large, the cross section does exhibit deep dips in regions of phase space corresponding to the position of the actual zeros. We show that in these regions the sensitivity to possible anomalous quartic couplings is very large.
The energy spectrum of leptons, produced by the decay of one or both W's in the reaction $e^+e^- \to W^+W^-$, is a significant probe of the helicity structure of this process. We calculate the energy spectrum $d σ/d E$ of a single decay lepton, as well as the two-dimensional energy distribution $d σ/d E_+dE_-$. We then consider a possible strong final state interaction in the longitudinally polarized state of the W^+W^- system, parametrized by a ρ-like resonance in the region of 1.8 TeV. We show that such a resonance produces measurable effects in the lepton spectrum at $\sqrt{s}=500$ GeV. The results are compared with those obtained from a non-resonant interaction approximated by a phase factor $e^{i δ}$ in the l=1 part of the W^+_LW^-_L amplitude.