EVIDENCE FOR DIRECT PHOTONS FROM QUARKS IN ELECTRON-POSITRON ANNIHILATION

Hadronic events from e+e--annihilations with a high energy isolated photon have been investigated at C.M. energies between 14 GeV and 44 GeV. A forward-backward asymmetry Aγ of the positively charged jet with respect to the incident positron direction has been found:Aγγ=-0.32±0.07, providing evidence for photon bremsstrahlung from quarks. The forward-backward asymmetry of all hadronic events at C.M. energies between 30 GeV and 36 GeV has been measured. The value, corrected for the limited polar angle acceptance of the detector, is:A=+0.021±0.005. © 1988 Springer-Verlag.