Constraints on additional Z bosons derived from neutrino-electron scattering measurements

We report new constraints on the existence of additional Z bosons derived from neutrino-electron scattering data. The analysis is based on data taken by the CHARM II Collaboration during five years of exposure of the detector to the wide band neutrino beam at CERN. The limits on the mass of these new particles are evaluated in the framework of E 6 superstring-inspired theories and Left-Right symmetric models. Limits on the so-called Z 1 are also reported.