Test der CP-Invarianz im Zerfall Z"0#->##tau#anti #tau# und Bestimmung des schwachen Dipolmomentes des #tau#-Leptons

Using 19742 Z"0#->##tau# anti #tau# decays, accumulated in 1991 and 1992 with the OPAL-detector at LEP, a direct test of CP-invariance in the neutral current reaction e"+e"-#->##tau#"+#tau#"- is performed by measuring CP-odd observables. They are proportional to the weak dipole moment of the #tau#-lepton. Employing a new method based on optimal CP observables constructed from the #tau# flight and spin directions more sensitive measurements on the real and - for the first time - the imaginary part of the weak dipole moment with highest possible signal to noise ratio is obtained. No evidence for a non-zero expectation value of the considered observables and hence for CP-violation is observed. An upper limit on the weak dipole moment of vertical stroke Re(d_#tau#"#omega#) vertical stroke <1.2x10"-"1"7 e cm and vertical stroke Im(d_#tau#"#omega#) vertical stroke <4.0x10"-"1"7 e cm with 95% confidence level is given. (orig.)Available from TIB Hannover: RR 8053(94-17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman