Measurement of Trilinear Gauge Couplings in e+e−e^+ e^- Collisions at 161 GeV and 172 GeV

Trilinear gauge boson couplings are measured using data taken by DELPHI at 161~GeV and 172~GeV. Values for $WWV$ couplings ($V=Z, \gamma$) are determined from a study of the reactions \eeWW\ and \eeWev, using differential distributions from the $WW$ final state in which one $W$ decays hadronically and the other leptonically, and total cross-section data from other channels. Limits are also derived on neutral $ZV\gamma$ couplings from an analysis of the reaction \eegi

Search for neutral heavy leptons produced in ZZ decays

Weak isosinglet Neutral Heavy Leptons (νm) have been searched for using data collected by the DELPHI detector corresponding to 3.3 × 106 hadronic Z0 decays at LEP1. Four separate searches have been performed, for short-lived νm production giving monojet or acollinear jet topologies, and for long-lived νm giving detectable secondary vertices or calorimeter clusters. No indication of the existence of these particles has been found, leading to an upper limit for the branching ratio BR(Z0 → νmν̄) of about 1.3 × 10-6 at 95% confidence level for νm masses between 3.5 and 50 GeV/c2. Outside this range the limit weakens rapidly with the νm mass. The results are also interpreted in terms of limits for the single production of excited neutrinos. © Springer-Verlag 1997

A SEARCH FOR CP VIOLATION IN K+- ---> PI+- PI0 GAMMA DECAYS

A search has been made for a charge asymmetry in the decay rates for K± → π±π0γ, which would indicate a CP violating transition. No asymmetry has been found in the Dalitz plot distribution for the decay, nor has any asymmetry been found in the decay rate for the charged pion kinetic energy range 55 to 90 MeV, to a precision of ±2.9%. © 1976

A search for cp-violating effects in the decays k+- ---> pi+- pi0 pi0

The charge asymmetry in the total decay rates for the τ′ decay modes of the charged K-mesons has been measured. There is no asymmetry at the precision level of ±0.0029. The implications of this result are discussed. © 1973