Most of the meeting consisted of a talk
on linear e+e- accelerators, focusing on the two most-developed designs, NLC (X-band) and TESLA. Norbert emphasized that only two linear accelerators have been built, the original SLAC and one at Kharkov. (From the perspective of an accelerator builder, SLC was an upgrade, because the rf technology was basically the same.) A lesson here is that a TeV-scale collider is a huge technological step, with consequences in many places, including the price-tag.Many properties of the accelerators seem to follow from the law that transverse wakefields grow as f3, where f is the rf frequency. This influences almost everything about the beam itself and the accelerator complex.
One issue that arose is an interplay between the time-structure of the beam and beam-related backgrounds. NLC is expected to have somewhat fewer photons and hadronic junk per bunch-crossing than TESLA. Within each bunch train, bunches in NLC are so close together that junk from one crossing may appear within the detector's time resolution of a real physics event from another crossing. Avi Yagil volunteered to look into this issue and report at a later meeting.
Finally, the Higgs working groups reported on their progress so far, mostly literature search.
By the way, the tutorial of the SLAC software for linear collider simulations on January 18 seems to have gone well.
The homework assignment until next time is to meet with your chosen subgroup. (Choose a subgroup if you haven't yet.) Subgroups should plan what they want to do.
The next full meetings are scheduled for Wednesday, February 2, 2000 with Staszek Jadach talking about event generators, and Wednesday, February 9, 2000, with Rick Van Kooten talking about work done on Higgs before Snowmass 1996.