BOUNDS ON g Z 5 FROM PRECISION LEP MEASUREMENTS

The parity violating but CP conserving anomalous three-gauge-boson coupling g Z 5 induces a universal contribution to the left-handed coupling of the Z boson to fermions. We find that the LEP measurements of the partial Z widths and lepton forward-backward asymmetries are sufficiently precise to place a bound of order | g Z 5 | less than ∼ 10%. This bound is significantly better than what can be obtained at present from rare K and B meson decays.