CP Violation in Heavy Neutrino Mediated e−e−→W−W−e^- e^- \to W^- W^-

We consider the reaction $e^- e^- \rightarrow W^- W^-$ mediated by possible heavy neutrino exchange at future LINAC energies of $\sqrt{s}>> 2 m_W$. This reaction is sensitive to CP phases of the neutrino mixing matrices, even at the level of Born amplitudes. Certain integrated cross-sections are shown to have the power to resolve the CP phases when the experimental configurations are varied. Asymmetries sensitive to CP violation (involving initial QED phases) for $e^- e^-$ and $e^+ e^+$ reactions are constructed and their consequences considered.Comment: 9 pages plain Latex and 4 figures available separately as uuencoded figure

Physics with Like-Sign Muon Beams

We point out that both the specific lepton number content and the high energies potentially attainable with muon-muon colliders make it advisable to consider the technical feasibility of including an option of like-sign incoming beams in the studies towards a proposal to build a muon-muon collider with center-of-mass energies in the TeV region. This capability will add some unique physics capabilities to the project. Special attention will have to be paid to polarization retention for the muons.Comment: 13 pages, uuencoded postscript file, also available from ftp://gluon.hep.physik.uni-muenchen.de/preprints/scipp9534.u

Model-Independent Z′Z' Limits from Electron-Electron Collisions

Model independent constraints on the mass of an extra neutral gauge boson and its couplings to charged leptons are given for the $e^-e^-$ option of a future linear collider. Analytic exclusion limits are derived in the Born approximation. The results are compared with those of the $e^+e^-$ mode. The influence of radiative corrections is discussed.Comment: 7 pages, LaTeX, 4 Figures, uuencoded Postscriptfile, MPI-Ph/94-23, LMU-04/9

On Possibility of Detecting the E-E- -> W-W- Process in the Standard Model

We examine the e-e- -> W-W- lepton number violating process in the frame of the Standard Model with additional right-handed neutrino singlets. We give results in the framework of the `see-saw' as well as other models, where there is no relation between neutrino masses and the mixing matrix elements. The cross section for the `see-saw' models is negligible because they predict in a natural way very small electron-heavy neutrino mixing angles. However, there exist other models, in which the electron-heavy neutrino mixing angles are free parameters and can be large. Taking into account the present experimental bounds on mixing angles the large cross section for the e-e- -> W-W- is still acceptable.Comment: 16 pages, LATEX file and 4 tar-compressed uuencoded figure

Accélérateurs et nouveaux concepts d'accélération de particules

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