We consider various integrated lepton charge-energy asymmetries and azimuthal asymmetries as tests of CP violation in the process e − e + → W − W + . These asymmetries are sensitive to different linear combinations of the CP violating form factors in the three gauge boson W − W + production vertex, and can distinguish dispersive and absorptive parts of the form factors. It makes use of purely hadronic and purely leptonic modes of W 's decays as well as the mixed modes. The techniques of using the kinematics of jets or missing momentum to construct CP-odd observables are also employed. These CP violating observables are illustrated in the generalized Left-Right Model and the Charged Higgs Model.

We investigate the possibility of detecting CP-odd angular correlations in the various decay modes of the neutral Higgs boson including the modes of a ZZ pair, a W + W − pair, or a heavy quark pair. It is a natural way to probe the CP character of the Higgs boson once it is identified. Final state interactions (i.e. the absorptive decay amplitude) is not required in such correlations. As an illustrative example we take the fundamental source of the CP nonconservation to be in the Yukawa couplings of the Higgs boson to the heavy fermions. A similar correlation in the process e + e − → l + l − H is also proposed. Our analysis of these correlations will be useful for experiments in future colliders such as LEP II, SSC, LHC or NLC.

We investigate possible CP violating effects in e + e − annihilation into top quark pairs. One of the interesting observable effects is the difference in production rates between the two CP conjugate polarized states t LtL and t RtR . The result is an asymmetry in the energy spectra of the lepton and the anti-lepton from the heavy quark decays. Another CP-odd observable is the up-down asymmetry of the leptons with respect to the reaction plane. These two asymmetries measure complementarily the absorptive and dispersive form factors of the electric dipole moment. Finally, as an illustration, we calculate the size of the CP violating form factors in a model where the CP nonconservation originates from the Yukawa couplings of a neutral Higgs boson.

We show that the simple Zee model of the neutrino mass already incorporates the interesting prediction of a large transitional neutrino magnetic moment. PACS nurnber(s): 14.60. Gh, 13.40.Fn The apparent anticorrelation of the neutrino flux with the sunspot cycle [I] suggests that neutrinos may have a magnetic moment. The magnetic moment required for this effect [2] is p, N 10-lo -1 0 -~l p~, where ,LLB is the Bohr magneton. It is difficult to understand how such a large magnetic moment is compatible with a small neutrino mass. In an inspiring Letter [3], Barr, Freire, and Zee (BFZ) consider a spin mechanism which provides for a large neutrino transitional magnetic moment /I,, but a relatively small neutrino mass. However, they concluded that, in order to illustrate the mechanism, an extension of the Higgs sector of the minimal Zee model [4] for neutrino mass is necessary. In contrast, we will show that the minimal Zee model already supports the realization of such a mechanism.The mechanism can be understood [3] on the basis of an approximate custodial flavor symmetry SU(2), between the electron and the muon species. Such a symmetry [5] forbids the neutrino from being massive while allowing p,. In the standard model, when the Yukawa couplings associated with the electron and muon masses are set to zero, an SU(2), symmetry of this type automatically arises. It is therefore tempting to take advantage of such accidental approximate symmetry even in an extension of the standard model with lepton-number breaking. The idea ties up the smallness of the neutrino masses with the smallness of the Yukawa couplings of the electron and muon. Of course, to generate p,, we need lepton-number symmetry breaking, which has to be implemented within the sector where the custodial symmetry is preserved.The essential ingredients mentioned above are all contained in the Zee model [4]. The model used one charged SU(2)L singlet h+ and two doublets of Higgs + i , i = 1,2, instead of three doublets'as in the simplest example pro-vided by BFZ. The third doublet is employed by BFZ to circumvent a technical problem in generating two-loop graphs for neutrino magnetic moments. However, in that analysis they overlooked a quartic scalar self-coupling, and when that coupling is included, the minimal Zee I

We show how a list of symmetry principles can be used to generate a class of models in which the neutrino masses are suppressed while relatively large magnetic moments are allowed. The simplest example is a model for neutrino mass proposed by Zee some time ago. We show how the model can be improved based on the symmetry principle and we also demonstrate other models in this class which avoid some of the weakness in the simplest model.