Author/Authors :
OPAL Collaboration، نويسنده , , G. Abbiendi، نويسنده , , K. Ackerstaff، نويسنده , , G. Alexander، نويسنده , , J. Allison، نويسنده , , N. Altekamp، نويسنده , , K.J. Anderson، نويسنده , , S. Anderson، نويسنده , , S. Arcelli، نويسنده , , S. Asai، نويسنده , , S.F Ashby، نويسنده , , D. Axen، نويسنده , , G. Azuelos، نويسنده , , A.H. Ball، نويسنده , , E. Barberio، نويسنده , , R.J. Barlow، نويسنده , , R. Bartoldus، نويسنده , , J.R. Batley، نويسنده , , Leslie S. Baumann، نويسنده , , J. Bechtluft، نويسنده , , et al.، نويسنده ,
Abstract :
We report the first observation of Z/γ∗ production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e−→e+e−Z/γ∗, where one of the final state electrons is undetected. Approximately 55 pb−1 of data collected in the year 1997 at an e+e− centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/γ∗ from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/γ∗ branching ratio to hadrons to be (0.9±0.3±0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)eγ∗ production, this product is found to be (4.1±1.6±0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.
