Status for a Linear Collider

The physics case for a Linear Collider with high luminosity and polarized beams has been clearly worked out (, ). There exists a `world-wide' (ACFA, ECFA, US HEPAP subpanel report, Statement by Snowmass Physics Groups) agreement that the next huge facility in our field shall be a Linear Collider with at least an energy of sqrt{s}=400~GeV. Moreover a time overlap between LHC and the future LC could be very constructional for the physics analysis at both machines. Probably, within about the next five years the political decisions will show whether a LC is approved and where it will be built.

Why this working group?

The use of beam polarization is a very powerful tool for the linear collider both for discovering and analysing new physics as well as for precision analyses. Snowmass 2001 provides an intensive exchange of status reports on polarization issues. However, there are still open questions concerning in particular the polarization of the positron beam. Polarized positrons are e.g. needed for applying the Blondel Scheme for high precision analyses. But also for studies of New Physics e.g. SUSY simultaneously polarized electron and positron beams are very helpful or even absolutely needed as e.g. for the verification of the fundamental SUSY assumption that chiral fermions are associated to scalar SUSY partners. And the studies are even ongoing. Therefore at Cracow on the first meeting of the Extended Joint ECFA/DESY Study on Physics and Detectors for a Linear Electron-Positron Collider it was initiated that one forms a group of polarization experts from machine, experiment and theory in order to focus on new developments in beam polarization.

How should it work?

It is planned to send occasionally emails to the members ('You'), asking for news on polarization issues or problems which need discussions. Eventually, it would be possible to ask for some time slots at e.g. Extended EFCA/DESY workshops for future Linear colliders or to have some own meetings where we only discuss these news so that we are up to date either from experimental view but also from machine status and that are prepared when we get the o.k. for the LC.

For this reason this homepage (, which is still under construction!), shall provide an overview on polarization issues (see link to Papers, soon available), on the results and problems which have to be tackled. Therefore hints from You for links to papers or proposals for topics are very welcome! Please, send only an email.