Measurement of Z/γ* production in compton scattering of quasi-real photons
Published online: 5 April 2002
The process e+e- → e+e- Z/γ* is studied with the OPAL detector at LEP at a centre of mass energy of √s = 189 GeV. The cross-section times the branching ratio of the Z/γ* decaying into hadrons is measured within Lorentz invariant kinematic limits to be (1.2 ± 0.3 ± 0.1) pb for invariant masses of the hadronic system between 5 GeV and 60 GeV and (0.7 ± 0.2 ± 0.1) pb for hadronic masses above 60 GeV. The differential cross-sections of the Mandelstam variables ͡s, ͡t, and ͡u are measured and compared with the predictions from the Monte Carlo generators grc4f and PYTHIA. From this, based on a factorisation ansatz, the total and differential cross-sections for the subprocess eγ → eZ/γ* are derived.
© Società Italiana di Fisica, Springer-Verlag, 2002